Method and Apparatus for Measuring Dimension of Circuit Patterm Formed on Substrate by Using Scanning Electron Microscope

ABSTRACT

In the dimension measurement of a circuit pattern using a scanning electron microscope (SEM), in order to make it possible to automatically image desired evaluation points (EPs) on a sample, and automatically measure the circuit pattern formed at the evaluation points, according to the present invention, in the dimension measurement of a circuit pattern using a scanning electron microscope (SEM), it is arranged that coordinate data of the EP and design data of the circuit pattern including the EP are used as an input, creation of a dimension measurement cursor for measuring the pattern existing in the EP and selection or setting of the dimension measurement method are automatically performed based on the EP coordinate data and the design data to automatically create a recipe, and automatic imaging/measurement is performed using the recipe.

BACKGROUND OF THE INVENTION

The present invention relates to a scanning electron microscope (SEM)capable of imaging a desired evaluation point on a sample andautomatically measuring a desired dimension of a circuit pattern formedat the evaluation point, and to a measuring method therefor.Specifically, the present invention relates to an SEM device providedwith an automatic recipe creating function of obtaining an SEM image ofthe desired evaluation point and automatically determining a recipemaking it possible to perform a desired measurement (e.g., a measurementof wiring width of the line pattern or a measurement of a gap betweenthe line patterns) at the evaluation point based on the design data ofthe circuit pattern without using a real wafer, and to a measuringmethod therefor. In the recipe, there are designated an imaging methodof the SEM image of the evaluation point, a position and a shape of adimension measurement cursor for measuring the dimension in the desiredcircuit pattern after taking the SEM image, and a dimension measurementmethod.

When forming a wiring pattern on a semiconductor wafer, there is adopteda method in which a coating material called resist is applied on thesemiconductor wafer, an exposure mask (a reticle) for the wiring patternis stacked on the resist, a visible light beam, an ultraviolet ray, oran electron beam is applied on the exposure mask, thereby exposing theresist to be developed, thus forming the wiring pattern with the resiston the semiconductor wafer, and then an etching treatment is executed onthe semiconductor wafer using the wiring pattern, which is made of theresist, as a mask, thereby forming the wiring pattern. Since the wiringpattern made of the resist varies in the form of the pattern dependingon the intensity and aperture of the visible light beam, the ultravioletray, of the electron beam applied to the wiring pattern, it is necessaryto examine the facture of the pattern in order to form a highly accuratewiring pattern. In the examination described above, critical dimensionscanning electron microscopes (CD-SEM) have been used widely in thepast.

The coordinate point, at which the SEM imaging is performed forevaluating the pattern shape, is called an evaluation point, andhereinafter abbreviated as EP. The EP is designated by the user in somecases, or provided by the coordinates of a hot spot (a critical point)on the semiconductor pattern to be examined in other cases. Thecoordinates of the hot spot can be estimated by an exposure simulationor the like. Various dimensional values such as the wiring width of thepattern are measured based on the SEM image, and the facture of thepattern is evaluated based on these dimensional values. The result ofthe evaluation is fed-back to a shape correction of the mask pattern andsemiconductor manufacturing process conditions, thus a high yield isrealized.

In order to take an image of the EP with a small amount of imagingposition misalignment and a high image quality, the following process isexecuted prior to the imaging of the EP. Firstly, some or all ofadjustment points such as an addressing point (hereinafter referred toas AP), an automatic focus adjustment point (hereinafter referred to asAF), an automatic astigmatism adjustment point (hereinafter referred toas AST), or an automatic brightness/contrast adjustment point(hereinafter referred to as ABCC) are set if necessary. Then,addressing, an automatic focus adjustment, an automatic astigmatismadjustment, or an automatic brightness/contrast adjustment is executedat the respective adjustment points. The amount of imaging positionmisalignment in the addressing described above is corrected using anamount of matching difference as the amount of position misalignment ofimaging. The amount of matching is obtained by matching an SEM image atthe AP with known coordinates previously registered as a registeredtemplate and an SEM image (a real imaging template) observed in theactual imaging sequence with each other. The evaluation point (EP) andthe adjustment points (AP, AF, AST, and ABCC) are collectively calledimaging points. A position and imaging conditions of EP, and an imagingsequence and imaging conditions, an adjustment method, and theregistered template of each of an imaging sequence for taking an imageof the EP are managed as an imaging recipe, and the SEM executes imagingof the EP based on the imaging recipe.

When the SEM image at the EP is obtained, a desired dimension of thesemiconductor pattern at a measurement point (hereinafter referred to asMP) to be measured in the EP using the SEM image.

Conventionally, the operator of the SEM manually create the recipe, andthe creation of the recipe is an operation requiring energy and time.Further, since in order to register the determination of each of theadjustment points and the registered templates in the recipe, it isrequired to actually take an image of the wafer at low magnification,the creation of the recipe is a factor of lowering the operation rate ofthe SEM device. Further, as the pattern becomes miniaturized andcomplicated, the number of EP required to be evaluated increasesexplosively, and it is getting unrealistic to create the recipe manuallyfrom viewpoints of energy and creation time.

Therefore, regarding the imaging recipe, there is disclosed, inJP-A-2002-328015, a semiconductor inspection system for determining theAP based on the design data of the circuit pattern of the semiconductordescribed in, for example, GDSII format, further clipping the data inthe AP out of the design data, and registering the data in the AP to theimaging recipe as the registered template. In this dace, since there isno need for taking an image of a real wafer only for the purpose ofdetermination of the AP and registration of the registered template,improvement of operation rate of the SEM can be achieved. Further, thesystem has a function of matching, when the SEM image (a real imagetemplate) at the AP has been obtained in the actual imaging sequence,the real image template and the registered template in the design datawith each other, re-registering the SEM image corresponding to theposition of the registered template of the design data to the imagingrecipe as the registered template, and thereafter using the registeredtemplate of the SEM image thus re-registered in the addressingprocessing. Further, the system has a function of automaticallydetecting a characteristic part of the pattern from the design data, andregistering the part as the AP.

Further, JP-A-2007-250528 describes a method of creating the imagingrecipe for observing the EP using CAD data. The document describes thatsome or all of the items including the number, coordinates, anddimensions/shapes of imaging points, an imaging sequence, a method ofchanging an imaging position, and imaging conditions necessary for theobservation are automatically obtained from the CAD data. The documentfurther describes that an operation of creating the image recipe isexecuted offline using the CAD data instead of the SEM image of a realwafer.

In other words, in the related art, the specification and thecharacteristics of the measurement tool (SEM) side for realizing themeasurement expected by the user at the EP has not been considered.Therefore, there have arisen many cases in which correction of therecipe by the operator is required after the recipe has been created.

Further, in the related art, there has been made no consideration ofsharing the recipe creation system and the information created orobtained by the system among a plurality of SEM devices, and therefore,recipe creation is required to be executed by every device. Further,there has been made no consideration of sharing the imaging/measurementdata obtained from a plurality of devices.

SUMMARY OF THE INVENTION

The present invention relates to an SEM device provided with anautomatic creation function for the imaging/measurement recipe and amethod therefor, and is in particular for providing a recipe creationmethod expected to solve the following problems arising in the automaticcreation of the measurement recipe thereby reducing the correction ofthe recipe by the operator, and improving the accuracy of imaging ormeasurement compared to the related art.

Specifically, according to the present invention, it becomes possible tocreate the recipe of the SEM in a waferless and offline (without usingthe SEM device) condition, and in an automatic manner by using thedesign data.

Further, in the recipe creation procedure, it is arranged to makeconsideration not only of the viewpoint of simply taking an image of theEP designated by the user, but also of the specification and thecharacteristics of the measurement tool (SEM) side for realizing themeasurement expected by the user at the EP.

Further, it is arranged that the recipe creation system and theinformation created or obtained by the system are shared among aplurality of SEM devices.

Specifically, in order to solve the problems described above, in thepresent invention, a method of measuring a dimension of a circuitpattern formed on a substrate using a scanning electron microscope,includes the steps of

(a) inputting a position information of a circuit pattern having adimension to be measured out of the circuit pattern formed on thesubstrate, and design information of the circuit pattern including thecircuit pattern having the dimension to be measured, and formed on thesubstrate,

(b) setting a measurement object area including an edge of the circuitpattern having the dimension to be measured using the positioninformation of the circuit pattern having the dimension to be measuredand the design information, and an imaging area and an imaging conditionfor imaging an area including the measurement object area thus set witha scanning electron microscope,

(c) setting an imaging sequence for imaging the imaging area with thescanning electron microscope for measuring the dimension of the circuitpattern,

(d) imaging the circuit pattern formed on the substrate with thescanning electron microscope based on the imaging condition and theimaging sequence, and

(e) processing the image obtained by imaging to measure the dimension ofthe circuit pattern, wherein

step (b) includes the steps of setting, as an area including a positionat which the dimension of the circuit pattern is measured, an areaincluding the edge of the circuit pattern in the vicinity of theposition at which the dimension of the circuit pattern is measured, andsetting in accordance with a direction of the edge of the circuitpattern included in the area, a direction of continuous scanning of anelectron beam scanned in the scanning electron microscope.

Further, in order to solve the problems described above, in the presentinvention, a method of measuring a dimension of a circuit pattern formedon a substrate using a scanning electron microscope, includes the stepsof

(a) inputting a position information of a circuit pattern having adimension to be measured out of the circuit pattern formed on thesubstrate, and design information of the circuit pattern including thecircuit pattern having the dimension to be measured, and formed on thesubstrate,

(b) setting a measurement object area including an edge of the circuitpattern having the dimension to be measured using the positioninformation of the circuit pattern having the dimension to be measuredand the design information, and an imaging area and an imaging conditionfor imaging an area including the measurement object area thus set witha scanning electron microscope,

(c) imaging the circuit pattern formed on the substrate with thescanning electron microscope based on the imaging condition, and

(d) processing the image obtained by imaging to measure the dimension ofthe circuit pattern using information of the edge of the circuit patternhaving the dimension to be measured included in the imaging area,wherein

step (b) includes the steps of setting a type of the dimension to bemeasured using the position information of the circuit pattern havingthe dimension to be measured and the design information, and setting themeasurement object area in accordance with the type of the dimension tobe measured.

Further, in order to solve the problems described above, in the presentinvention, an apparatus adapted to measure a dimension of a circuitpattern formed on a substrate using a scanning electron microscope,includes

input means for inputting a position information of a circuit patternhaving a dimension to be measured out of the circuit pattern formed onthe substrate, and design information of the circuit pattern includingthe circuit pattern having the dimension to be measured, and formed onthe substrate,

imaging condition setting means including a measurement object areasetting section adapted to set a measurement object area including anedge of the circuit pattern having the dimension to be measured usingthe position information of the circuit pattern having the dimension tobe measured and the design information, and an area/condition settingsection adapted to set an imaging area and an imaging condition forimaging an area including the measurement object area thus set by themeasurement object area setting section with a scanning electronmicroscope,

imaging sequence setting means for setting an imaging sequence forimaging the imaging area, which is set by the imaging condition settingmeans for measuring the dimension of the circuit pattern, with thescanning electron microscope, scanning electron microscope means forimaging the circuit pattern formed on the substrate based on the imagingcondition set by the imaging condition setting means and the imagingsequence set by the imaging sequence setting means, and

image processing means for processing the image obtained by imaging withthe scanning electron microscope means to measure the dimension of thecircuit pattern, wherein

the measurement object area setting section of the imaging conditionsetting means sets, as an area including a position at which thedimension of the circuit pattern is measured, an area including the edgeof the circuit pattern in the vicinity of the position at which thedimension of the circuit pattern is measured, and

the imaging condition means further includes a scanning directionsetting section adapted to set a direction of continuous scanning of anelectron beam scanned in the scanning electron microscope in accordancewith a direction of the edge of the circuit pattern included in the areaset by the measurement object area setting section.

Further, in order to solve the problems described above, in the presentinvention, an apparatus adapted to measure a dimension of a circuitpattern formed on a substrate using a scanning electron microscope,includes

input means for inputting a position information of a circuit patternhaving a dimension to be measured out of the circuit pattern formed onthe substrate, and design information of the circuit pattern includingthe circuit pattern having the dimension to be measured, and formed onthe substrate,

imaging condition setting means including a measurement object areasetting section adapted to set a measurement object area including anedge of the circuit pattern having the dimension to be measured usingthe position information of the circuit pattern having the dimension tobe measured and the design information input by the input means, and anarea/condition setting section adapted to set an imaging area and animaging condition for imaging an area including the measurement objectarea thus set by the measurement object area setting section with ascanning electron microscope,

scanning electron microscope means for imaging the circuit patternformed on the substrate, based on the imaging condition set by theimaging condition setting means, and

image processing means for processing the image obtained by imaging withthe scanning electron microscope means to measure the dimension of thecircuit pattern using information of the edge of the circuit patternhaving the dimension to be measured included in the imaging area,wherein

the imaging condition setting means further includes a dimensionmeasurement type setting section adapted to set a type of the dimensionto be measured using position information of the circuit pattern havingthe dimension to be measured and the design information input by theinput means, and

the imaging condition setting means sets the area including the edge ofthe circuit pattern as the measurement object area in accordance withthe type of the dimension to be measured set by the dimensionmeasurement type setting section in the measurement object area settingsection.

In the present invention, when the SEM image at the EP is obtained, adesired dimension of the semiconductor pattern at a measurement point(hereinafter referred to as MP) to be measured in the EP using the SEMimage. As the desired dimension, a line width of the line pattern, anamount of gap between the line patterns, and so on can be cited, andhereinafter such variations of measurement in the MPs are calleddimension measurement types. In some cases, a plurality of MPs exists inthe EP. Then, an example of a measurement method will be explainedexemplifying the measurement of a line width (a distance between theright and left edges of a line) of a line pattern as the dimensionmeasurement type. In order to measure the line width correctly, it isrequired to accurately and stably measure the positions of the right andleft edges of the line. Therefore, there is a method in which an areawith a predetermined dimension including the edge is set on each of theright and the left edges, and a cumulative profile less subject to theimage noise or the line edge roughness is obtained by accumulating theSEM signal in the area in the line direction, and the edge position isdetected using the profile. The measurement object area (the area on theSEM image referred to by obtaining the measured value) with apredetermined dimension including the edge is designated by a box calleda dimension measurement cursor. The position and the shape of thedimension measurement cursor, a dimension measurement method (adimension measurement algorithm and a dimension measurement parameter)are managed as a measurement recipe, and the SEM performs themeasurement at the EP based on the measurement recipe.

In the present specification, the terms an imaging recipe and ameasurement recipe are used along the definitions described above. Itshould be noted that the definitions of the imaging recipe and themeasurement recipe are nothing more than an example, the setting itemsdesignated by the respective recipes can be managed in arbitrarycombinations. Therefore, in the case in which the imaging recipe and themeasurement recipe are not particularly discriminated, both recipes arecollectively called simply a recipe or an imaging/measurement recipe.

According to the present invention, it becomes possible for everyone toautomatically and quickly create the highly accurate recipe in thewaferless condition and without an extraordinary knowledge about theSEM. The advantages of the present invention can be summarized as thefollowing items (1) through (3).

-   (1) By using the design data, it becomes possible to automatically    create the recipe of the SEM in a waferless, offline (without using    the SEM device) condition, which leads to reduction of burden of the    operator and improvement of the operation rate of the SEM device.    Further, the automation of the operation allows the recipe creation    independent of difference in skill between the operators.-   (2) In the recipe creation procedure according to the present    invention, since the specification and characteristic of the    measurement tool (SEM) for realizing the measurement intended by the    user at the EP are also taken into consideration, in addition to the    viewpoint of simply imaging the EPs designated by the user, it can    be expected to reduce the frequency of the case in which the recipe    correction by the operator becomes necessary after the recipe has    once been created, and to improve the strictness of the imaging or    the measurement compared to the related art.-   (3) By sharing the recipe creation system and the information    created or obtained by the system among a plurality of SEM devices,    it can be eliminated to execute the recipe creation by every device.    Further, since the result data including successful cases and failed    cases in the imaging/measurement obtained from a plurality of    devices can be shared, it is possible to collect a lot of result    data quickly, and if a problem exists in the recipe creation rule,    for example, a measure against the problem can quickly be taken    based on the result data.

These and other objects, features and advantages of the invention willbe apparent from the following more particular description of preferredembodiments of the invention, as illustrated in the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram showing a configuration of an SEM device forembodying the present invention.

FIG. 2A is a diagram schematically showing the condition that electronsare emitted from a surface of a semiconductor wafer in response toscanning of an electron beam, and FIG. 2B is a diagram showing a methodof imaging the amount of signal obtained by detecting electrons emittedfrom the surface of the semiconductor wafer.

FIG. 3A is a flowchart representing an imaging sequence, and FIG. 3B isa diagram showing positions corresponding to respective imaging steps ofthe flowchart in a beam shift allowable area from evaluation points(EP).

FIG. 4 is a chart for showing an overall processing flow for creatingthe recipe.

FIG. 5 is a chart showing an estimation flow for a dimension measurementtype/measurement point in the evaluation point.

FIG. 6A is a diagram showing an example of the case in which thedimension measurement type is a line width of a line pattern, FIG. 6B isa diagram showing an example of the case in which the dimensionmeasurement type is a distance between the line patterns, FIG. 6C is adiagram showing an example of the case in which the dimensionmeasurement type is a gap between a line end section of the line patternand the line pattern, FIG. 6D is a diagram showing an example of thecase in which the dimension measurement type is an amount of recessionof the end section of the line pattern, FIG. 6E is a diagram showing anexample of the case in which the dimension measurement type is adiameter of a contact hole and the diameter is measured in tow or moredirections, FIG. 6F is a diagram showing an example of the case in whichthe dimension measurement type is a diameter of a contact hole and thediameter is measured in one direction, FIG. 6G is a diagram showing anexample of the case in which the dimension measurement type isdimensions of a major axis and a minor axis of the line pattern, FIG. 6His a diagram showing an example of the case in which the dimensionmeasurement type is a gap width between the line patterns, FIG. 6I is adiagram showing an example of the case in which the dimensionmeasurement type is a shape of the pattern, FIG. 6J is a diagramenlargedly showing a part of FIG. 6I, FIG. 6K is a diagram showing anSEM signal profile corresponding to the line between α and β shown inFIG. 6A, FIG. 6L is an enlarged diagram of FIG. 6A, FIG. 6M is a diagramshowing an example of the case in which the dimension measurement typeis a line width of the line pattern extending in the y direction, FIG.6N is a diagram showing an example of the case in which the dimensionmeasurement type is a line width of the line pattern extending in the xdirection, FIG. 6O is a diagram showing an example of the case in whichthe dimension measurement type is a line width of the line patternextending in the x direction and there is a view field misalignment inthe x direction, and FIG. 6P is a diagram showing an example of the casein which the dimension measurement type is a gap between the linepatterns, and a part of a dimension measurement cursor runs out of theview field due to the view field misalignment.

FIG. 7A is a diagram showing an example of two patterns included in theview field of the evaluation point (EP), FIG. 7B is a diagram showingthe design data corresponding to the EP shown in FIG. 7A, FIG. 7C is adiagram showing a pattern obtained by modifying the pattern as designed,FIG. 7D is a diagram showing an example of measurement points of theline patterns in the x direction estimated from the design data, FIG. 7Eis a diagram showing an example of measurement points of the endsections of line patterns in the y direction estimated from the designdata, FIG. 7F is a diagram showing an example of measurement points of agap between the line patterns estimated from the design data, and FIG.7G is a diagram showing an example of OPC shape measurement pointsestimated from the design data.

FIG. 8A is a diagram showing the case in which the line width of each ofthe six line patterns is measured, FIG. 8B is a diagram showing thecondition in which the measurement points of the six line patterns areset so as to be included in the view fields of the EPs, FIG. 8C is adiagram showing the condition in which the EPs are set to be optimizedso that the imaging ranges do not overlap with each other, FIG. 8D is adiagram showing the condition in which there exist three measurementpoints in the design data and the EP is set corresponding to each of themeasurement points, FIG. 8E is a diagram showing the condition in whichtwo EPs out of the three EPs corresponding respectively to the threemeasurement points are merged with each other, and FIG. 8F is a diagramshowing the condition in which two EPs, a different combination thereoffrom the combination shown in FIG. 8E, out of the three EPscorresponding respectively to the three measurement points are mergedwith each other.

FIG. 9A is a diagram showing the condition in which the dimensionmeasurement cursors are disposed on the design data, FIG. 9B is adiagram showing the line pattern observed by an SEM device, FIG. 9C is adiagram showing the condition in which the design data is matched withthe SEM image of the pattern, FIG. 9D is a diagram showing the conditionin which the dimension measurement cursors are displayed so as tooverlap on the SEM image, FIG. 9E is a diagram showing the condition inwhich the positions of the dimension measurement cursors are shifted inaccordance with the edge positions of the pattern on the SEM image, FIG.9F is a diagram showing an example in which a correction has been madeso as to extend the profile reference range outside the line pattern inthe case in which the skirt sections of the white band protrusions arelong in the SEM signal profile of the line pattern, FIG. 9G is a diagramshowing the design data of an upper layer pattern and a lower layerpattern, FIG. 9H is a diagram showing the patterns on the SEM imagecorresponding to the patterns on the design data shown in FIG. 9G, FIG.9I is a diagram showing the condition in which the patterns on thedesign data and the patterns on the SEM image are matched with eachother, and the dimension measurement cursors are disposed thereon, FIG.9J is an SEM image in the condition in which the upper layer pattern andthe lower layer pattern are misaligned to each other due to a fault inthe manufacturing process, and FIG. 9K is a diagram showing thecondition in which the patterns on the design data is matched with theSEM image in the condition in which the upper layer pattern and thelower layer pattern are shifted from each other, and the dimensionmeasurement cursors are disposed thereon.

FIG. 10A is a diagram showing two patterns on the design data and a pairof cursors for measuring the distance between the two patterns, FIG. 10Bis a diagram showing a matching result of the pattern of the SEM imageand the pattern as designed, FIG. 10C is an enlarged view of a part ofthe dimension measurement cursor shown in FIG. 10B, FIG. 10D is an SEMimage of the patterns with corners rounded due to the resolution limitof the lithography, and FIG. 10E is an enlarged view of a part of thedimension measurement cursor shown in FIG. 10D.

FIG. 11A is a diagram showing the condition in which eight EPs exist ina low magnification image area of the SEM, FIG. 11B is a part of a GUIshowing an initial imaging order, FIG. 11C is a part of the GUI showingthe imaging order with the reduced number of times of rotation comparedto the imaging order shown in FIG. 11B, FIG. 11D is a part of the GUIshowing the imaging order with the reduced total distance of view fieldmovement between the EPs compared to the imaging order shown in FIG.11B, and FIG. 11E is a part of the GUI showing the imaging orderdetermined in consideration of the time required for a rotation and thetime required for the view field movement between the EPs in the case inwhich the time required for a rotation and the time required for theview field movement between the EPs are roughly the same.

FIG. 12A is a diagram showing a configuration of an apparatus system forrealizing the present invention, and FIG. 12B is a diagram showing aconfiguration with some of the constituents of the system shown in FIG.12A are integrated with each other.

FIG. 13 is a diagram showing an example of the GUI screen according tothe present embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention relates to an SEM device provided with a functionof automatically creating the recipe with the following means, andexecuting automatic imaging/measurement using the recipe, and a methodtherefor.

(1) According to a feature of the present invention, coordinate data ofEPs and design data of circuit patterns including the EPs are used as aninput, creation of the dimension measurement cursor for measuring thepatterns existing in the EPs and selection or setting of the dimensionmeasurement method are performed automatically based on the EPcoordinate data and the design data. The dimension measurement cursorand the dimension measurement method are stored as a recipe. Byperforming the processing based on the resign data, there is no need fortaking an SEM image when creating the recipe, and therefore, theoperation can be carried out online, which leads to an improvement ofthe operation rate of the apparatus. As the coordinates of the EPs,there are input the coordinates of hot spots (critical points) detectedbased on the result of, for example, an exposure simulation executed byan EDA tool. Alternatively, in some cases, the coordinates of the EPsare input on a judgment of the user itself (taking the information ofthe EDA tool into consideration, if necessary).

In the creation of the dimension measurement cursor, the position andthe shape of the dimension measurement cursor are determined on thedesign data (the dimension measurement cursor has the coordinateslinking with the design data). Since the positional relationship betweenthe design data and the SEM image can be obtained by actually taking theSEM image of the corresponding EP and matching the design data and theSEM image with each other, and the positional relationship between thedimension measurement cursor and the SEM image can also be obtained atthe same time, the dimension measurement cursor can automatically bedisposed on the SEM image.

Further, the selection or setting of the dimension measurement methodspecifically denotes the selection or setting of a dimension measurementalgorithm or a dimension measurement parameter. The selection or settingdescribed above is executed taking the information such as a dimensionmeasurement type, or a shape or a direction of a pattern contour of thepattern to be measured into consideration if necessary.

(2) In the item (1) described above, in order to automatically createthe dimension measurement cursor, it is necessary to know thecoordinates of the measurement points (MP) to be measured in the EPs.Although there are some cases in which the EP coordinates (the centercoordinates of the EP area) match with the MP coordinates, there arealso the cases in which they do not match with each other, or the casesin which two or more MPs exist in the EP. Further, even if the MPcoordinates are provided by the input from the user, there is apossibility that the coordinate values include an error. Therefore,according to another feature of the present invention, the MPcoordinates are estimated inside the computer based on the coordinatedata of the EPs and the design data of the circuit pattern including theEPs, and the dimension measurement cursor is created based on the MPcoordinates thus estimated.

(3) In the item (1) described above, in order to automatically createthe dimension measurement cursor, it is necessary to know the dimensionmeasurement type of the MP in the EPs. In other words, the dimensionmeasurement cursor can hardly be set without understanding whatdeformation of the pattern possibly occurs at the MP, and whatdimensional value needs to be measured/controlled with respect to thedeformation. Further, it is not easy for the user to manually designateall of such dimension measurement types. Therefore, according to anotherfeature of the present invention, the dimension measurement types areestimated inside the computer based on the coordinate data of the EPsand the design data of the circuit pattern including the EPs, and thedimension measurement cursor is created based on the dimensionmeasurement types thus estimated. Here, the dimension measurement typesdenote the variations of measurement at the MP, and as specific examplesof the dimension measurement types, there are cited measurement of theline width of the line pattern, measurement of the gap between the linepatterns, measurement of the amount of recession of the line endsection, measurement of the diameter of the contact hole, measurement ofthe optical proximity correction (OPC) shape, and so on. Further, it ispossible to include the information of a region to be measured such asthe regions in the wiring area distance of which is measured in thedimension measurement type besides the category such as measurement ofthe line width. Further, it is also possible to include the informationof a measurement direction such as a direction an amount of recession inwhich is measured in the measurement of “an amount of recession” in thedimension measurement type.

(4) According to another feature of the present invention, in the item(3) described above, a candidate (hereinafter, referred to as acandidate defect) of a possible defect in the EPs is provided, thedimension measurement type is estimated based on the information of thecandidate defect, and the dimension measurement cursor is created basedon the dimension measurement type thus estimated. The candidate defectdenotes a defect mode in which the patterns can be linked with eachother, or the pattern can be broken, for example. It is possible toinput the candidate defect with the highest possibility of occurrencereferring to the analysis result by, for example, EDA tool, or to inputthe candidate defect the user wants particularly to avoid. It ispossible to input two or more candidate defects. How the SEM, themeasurement tool, measures the MP (i.e., the dimension measurement type)is determined based on the information of the candidate defect so as toreflect the intension of the user on managing the shape of the patternat the EP.

(5) According to another feature of the present invention, in the items(2) and (3) described above, in the estimation of the dimensionmeasurement type/MP, at each of the pattern regions obtained from thecircuit design pattern including the EPs, attribute information composedof at least one combination of a candidate of the dimension measurementtype, a candidate of a possible defect, a circuit attribute, easiness ofdeformation, measurement dimension on the design data, and the distancefrom the center of the evaluation point is calculated, and the candidateof the dimension measurement type/MP at the EP is extracted along theestimation rule based on the attribute information. By taking aplurality of pieces of attribute information into consideration, theestimation of the dimension measurement type/MP with high accuracybecomes possible.

(6) In the item (5), in some cases, the creation of the estimation rulebecomes a difficult operation for the user. Further, the defaultestimation rule prepared by the system can be different from thecriteria of the user. Therefore, according to another feature of thepresent invention, as a mechanism for easily executing the usercustomization, the estimation rule is optimized in response to at leastone combination teaching of EP and the position of the MP at the EP, ora combination teaching of the EP and the dimension measurement type atthe EP.

(7) According to another feature of the present invention, in the item(1) described above, SEM imaging conditions at the EP are obtained basedon the circuit design pattern including the EPs, and the conditions arestored in a recipe. According to another feature, the SEM imagingconditions include at least the scanning direction of the electron beam.Although the raster scan is common in the two-dimensional scanning ofthe electron beam for creating the SEM image, the obtained SEM image isdifferent between, for example, the case in which the scanning of thetwo-dimensional area is performed by executing continuous electron beamscanning in the x direction a plurality of times while shifting thescanning position discretely in the y direction, and the case in whichthe scanning of the two-dimensional area is performed by executingcontinuous electron beam scanning in the y direction a plurality oftimes while shifting the scanning position discretely in the xdirection. Therefore, it is effective to automatically setting thescanning method with which the SEM image advantageous to the measurementtaking the measurement region and the measurement direction in the EPinto consideration. The scanning method is not limited to the scanningin the direction parallel to the x or y direction, but can havevariations such as scanning in an oblique direction or scanning in thedirection varying in accordance with the position in the EP.

(8) According to another feature of the present invention, in the item(1) described above, the imaging range or the coordinates of the EP isoptimized based on the information of the dimension measurement cursor.The imaging range should be determined from the viewpoint that themeasurement of the desired region in the MP is realized with appropriatemeasurement accuracy in addition to the viewpoint of the range the userwants to check. Therefore, it is necessary to set the imaging range soas to include at least the range of the dimension measurement cursorrequired from the viewpoint of measurement accuracy. Further, it ispossible to change the coordinates of the EP provided by the user ifnecessary. The optimization of the EP coordinates includes principallythree items, (a) changing the coordinates of the EP and the imagingrange, (b) merging a plurality of view fields of the EPs to newly set asingle EP, and (c) dividing one EP to set a plurality of EPs, and anycombinations of these items. Specific examples of the contents of theprocessing and the advantages of the respective cases will be describedbelow.

In the case of (a), if the position of the MP (or the imaging areaincluding the dimension measurement cursor necessary for measurement) isfound, it becomes possible to determine whether or not the center of theEP is shifted from the MP, and if it is shifted, it becomes possible totake the image of the MP at roughly the center of the view field of theEP by matching the view field of the EP with the center of the MP.Further, for example, it is possible to adjust the imaging range so thatthe range of the dimension measurement cursor is sufficiently includedin the view field of the EP with respect to the imaging misalignment.

In the case of (b), when imaging/measuring dense continuous patterns insequence, for example, in some cases, the imaging ranges setrespectively to the patterns overlap with each other. In this case, whentaking an image of a certain EP, there is a possibility of causingcontamination in the measurement area (the area of the SEM imagenecessary for performing measurement) included in another EP, thusdegrading the measurement accuracy. Therefore, by resetting the EP areaso that the patterns included in the respective EPs are collectivelyincluded in a single view field, the contamination in the measurementarea described above can be prevented from occurring. When merging theEPs, the determination thereof can be made taking whether or not thedimension of the view field or the imaging magnification of the EPobtained by merging is within a predetermined dimension (since themeasurement accuracy is generally lowered with the lower magnification)and whether or not the SEM imaging conditions (e.g., scanning directionof the electron beam) of the EPs to be merged match each other intoconsideration.

In the case of (c), if a plurality of MPs are included in the EP, andfurther, the directions of the patterns to be measured in the respectiveMPs are different from each other, and therefore, the SEM imagingconditions (e.g., the scanning direction of the electron beam) isrequired to be different between the MPs, it is effective to separatethe MPs from each other as the EPs, thus taking images with the SEMimaging conditions different from each other. Further, in the case inwhich a number of MPs are included in the EP, and the MP is locatedclosest to the edge of the view field of the EP, there is a possibilitythat a part of the measurement area of the MP runs off the view fielddue to the view field misalignment caused when taking the image of theEP. In such a case, division of the EP is effective.

(9) In the item (1) described above, it is required to set the order oftaking the images of the EPs to the recipe when taking the images of aplurality of EPs. According to another feature of the present invention,the imaging order is optimized based on the coordinates of the EP andthe SEM imaging conditions of the EP instead of directly taking theinputting order of the EPs by the user as the imaging order. In order toimprove the throughput of the imaging in the EPs as a whole, it iseffective to reduce the total moving distance of the stage shift and theimage shift of the SEM. Further, it is also effective to decrease thenumber of times of the imaging condition changes taking the timenecessary for changing the imaging conditions into consideration.Therefore, the imaging order with which the throughput is enhanced isdetermined based on the coordinates of the EPs and the EPs or the SEMimaging conditions.

(10) When actually imaging/measuring the EPs using the recipe created ina waferless condition without using the SEM device, the shape misfitbetween the pattern actually formed on the wafer and the pattern on thedesign data might be a problem. Therefore, according to another featureof the present invention, after automatically disposing the dimensionmeasurement cursor on the SEM image of the EP in the item (1) describedabove, the shape misfit between the pattern in the SEM image and thepattern in the design data is calculated, thus correcting the positionor the shape dimension measurement cursor based on the shape misfitinformation. According to the present processing, it becomes possible tocorrectly measuring the dimension even if the shape and the position ofthe actual pattern are different from those of the design data to acertain extent.

(11) Some of the items designated by the recipe cannot accurately bedetermined only with the design data. In the case, for example, ofmeasuring the amount of recession of the line end section, although itis required to accurately detect the position of the line end section,in some cases, the corner sections of the pattern are rounded withrespect to the mask pattern due to the resolution limit of thelithography. In the case in which there is a straight section with anenough length, it is possible to use an algorithm for detecting the lineend section by applying the straight section. In the case in which arounded section is dominant, it is possible to use an algorithm fordetecting the line end section by applying the rounded section. However,there is a limit in estimating the extent of rounding of the line endsection based only on the design data. Further, the extent of roundingcan be varied in accordance with the variation in the manufacturingprocess. In order to solve such a problem, according to another featureof the present invention, a part of or the whole information of thedimension measurement method is changed based on the SEM image describedabove. The item (10) described above and the present item (11) aremechanisms for making the recipe, which is created based on the designdata in the waferless condition, appropriately applicable to the realpatterns.

(12) According to another feature of the present invention, at least onecombination of the coordinates of the EP, the design data, the dimensionmeasurement type/MP, the creation rule of the recipe, the recipe thuscreated, the image taken by the actual imaging sequence, the measurementresult, and success and failure of one of the imaging and measurement ismanaged in a database while being associated with each other, thusmaking it possible to share the recipe among two or more SEM devicesthrough a network or the like.

Then, the present invention will specifically be explained withreference to FIGS. 1 through 13.

1. SEM

1.1. Constituents of SEM

FIG. 1 shows a block diagram of a schematic configuration of a scanningelectron microscope (SEM) for obtaining a secondary electron image (SEimage) or a backscattered electron image (BSE image) of a sampleaccording to the present invention. Further, the SE image and the BSEimage are collectively called an SEM image. Further, the images obtainedhere include some or all of top-down images obtained by applying theelectron beam in a vertical direction to the measurement object andtilted images obtained by applying the electron beam in a desired tilteddirection.

An electron optical system 102 is provided with an electron gun 103inside thereof, and generates an electron beam 104. The electron beamemitted from the electron gun 103 is condensed to be a narrower beam bya condenser lens 105. Then, a deflector 106 and an objective lens 108control an application position and an aperture of the electron beam sothat the electron beam is applied in a focused condition at a desiredposition on the semiconductor wafer 101 as a sample placed on a stage117. Form the semiconductor wafer 101 irradiated with the electron beam,a secondary electron and a backscattered electron are emitted. Asecondary-electron detector 109 detects the secondary electron movingalong a path separated from the path of the applied electron beam by anExB deflector 107. Meanwhile, backscattered-electron detectors 110, 111detect the backscattered electron. The backscattered-electron detectors110 and 111 are respectively disposed in directions different from eachother. The secondary electron and the backscattered electronrespectively detected by the secondary-electron detector 109 and thebackscattered-electron detectors 110, 111 are converted by the A/Dconverters 112, 113, and 114 into digital signals, and the digitalsignals are input to the processing control section 115, stored in animage memory 122. A CPU 121 executes an image processing correspondingto a purpose on the digital signals.

FIGS. 2A and 2B show a method of imaging the amount of signal of theelectron emitted from the surface of the semiconductor wafer when theelectron beam is applied on the semiconductor by scanning the electronbeam thereon. The electron beam is applied while scanning in the x and ydirections in a manner illustrated with the lines 201 through 203 and204 through 206 as shown in, for example, FIG. 2A. It is possible tochange the scanning direction by changing the deflecting direction ofthe electron beam. The positions on the semiconductor wafer at which theelectron beam 201 through 203 scanned in the x direction are denotedwith G1 through G3, respectively. Similarly, the positions on thesemiconductor wafer at which the electron beam 204 through 206 scannedin the y direction are denoted with G4 through G6, respectively. Theamounts of signals of the electrons emitted in the positions G1 throughG6 correspond to the brightness values of pixels H1 through H6 in animage 209 shown in FIG. 2B, respectively (the subscripts 1 through 6 ofG and H correspond to each other). The reference numeral 208 is acoordinate system indicating the x and y directions on the image. Bythus scanning the inside of the view field with the electron beam, theimage frame 209 can be obtained. Further, in reality, by scanning theinside of the view field with the electron beam several times in thesame manner, and averaging the image frames thus obtained, an image witha high S/N can be obtained. The number of accumulated frames can be setaccording to needs.

The processing control section 115 shown in FIG. 1 is a computer systemequipped with a CPU 121 and an image memory 122, and performs processingcontrol such as sending control signals to a stage controller 119 or adeflection control section 120 based on the recipe in order to takeimages of the imaging points, or executing various kinds of imageprocessing on the taken images at the desired imaging points on thesemiconductor wafer 101. Here, the imaging points include some or all ofan addressing point (hereinafter referred to as AP), an automatic focusadjustment point (hereinafter referred to as AF), an automaticastigmatism adjustment point (hereinafter referred to as AST), anautomatic brightness/contrast adjustment point (hereinafter referred toas ABCC), and an evaluation point (hereinafter referred to as EP).Further, the processing control section 115 is connected to a processingterminal 116 (equipped with input/output means such as a display, akeyboard, and a mouse), and is provided with a graphic user interface(GUI) for displaying images to the user and accepting an input from theuser. The reference numeral 117 denotes an XY stage for moving thesemiconductor wafer 101, thereby making it possible to take images atdesired positions on the semiconductor wafer. A change of the imagingposition by the XY stage 117 is referred to as a stage shift. A changeof the observation position by, for example, deflecting the electronbeam with the deflector 106 is referred to as a beam shift. In general,the stage shift has characteristics of a large movable range and lowerpositioning accuracy of the imaging position, and in contrast, the beamshift has characteristics of a small movable range and higherpositioning accuracy of the imaging position.

Although FIG. 1 shows an embodiment equipped with two detectors of thebackscattered-electron image, it is possible to eliminate the detectorsof the backscattered-electron image, or to decrease or increase thenumber of detectors of the backscattered-electron image.

The computer system 115 described above creates the recipe with themethod described later, and controls the SEM device based on the recipe,thereby performing the imaging/measurement of the EP. It is possible toexecute the processing control by sharing a part or the whole of theprocessing control with a plurality of separate processing terminals.The detail will be explained later with reference to FIGS. 12A and 12B.Further, the reference numeral 123 is a database storing coordinates ofthe EPs and design layout information (hereinafter referred to as designdata) of a semiconductor circuit pattern formed on the wafer 101, whichform an input to the computer system 115 for creating theimaging/measurement recipe. Further, it is also possible to store themeasurement results and the recipes created in the computer system 115for sharing the results and the recipes.

As the method of obtaining the tilted image of the measurement objectobserved in a desired tilted direction using the apparatus shown in FIG.1, there can be cited (1) a method of deflecting the electron beamapplied from the electron optical system to vary the application angleof the electron beam, thereby taking the tilted image (e.g.,JP-A-2000-348658), (2) a method of tilting the stage 117 itself formoving the semiconductor wafer (the stage is tilted with a tilt angle118 in FIG. 1), and (3) a method of mechanically tilting the electronoptical system itself.

1.2. SEM Imaging Sequence

Regarding the imaging of the EP using the SEM described above, asupplementary explanation will be presented exemplifying the typicalimaging sequence including the imaging of the AP, the AF, the AST, andABCC shown in FIG. 3A.

Firstly, in the step 301 of FIG. 3A, the semiconductor wafer as a sampleis attached on the stage 117 of the SEM device. In the step 302, byobserving the global alignment mark on the wafer with the opticalmicroscope or the like, origin misalignment of the wafer and rotation ofthe wafer are corrected.

In the step 303, the stage 117 is moved based on the control andprocessing of the processing control section 115 to move the imagingposition to the AP for taking an image, a parameter for addressing isobtained, and then addressing is preformed based on the parameter thusobtained. Here, an explanation of the addressing will be added. In thecase of observing the EP, if it is attempted to directly observe the EPusing the stage shift, there is a possibility that the imaging positionis significantly shifted due to the positioning accuracy of the stage.Therefore, the AP previously provided with the coordinates and thetemplate (the pattern of the imaging point; either of the data formatsof the SEM image and the design data can be adopted) of the imagingpoint is once observed for the purpose of positioning. The template isregistered in the recipe, and therefore, hereinafter referred to as aregistered template.

The AP is selected from the peripheral area (the range accessible withthe beam shift) of the EP. Further, since the AP is generally a lowermagnification view field compared to the EP, there is a low possibilitythat all of the patterns in the registered template becomes out of theview field with respect to a certain extent of the imaging positionmisalignment. Therefore, by matching the registered template of the APand the SEM image (real imaging template) of the AP actually taken witheach other, the amount of position misalignment at the AP can beestimated. Since the coordinates of the AP and the EP are know, therelative displacement vector between the AP and the EP can be obtained,and in addition, since the amount of the position misalignment of theimaging point at the AP can also be estimated by the matching describedabove, by subtracting the amount of the position misalignment from anamount of the relative displacement described above, the relativedisplacement vector from the imaging position of the AP to the EP, whichshould actually be traced, can be obtained. By moving the beam using thebeam shift with a high positioning accuracy as much as the relativedisplacement vector described above, it becomes possible to take theimage of the EP with a high coordinate accuracy.

In the step 304, based on the control and processing of the processingcontrol section 115, the imaging position is moved to the AP using thebeam shift, thus taking an image, a parameter for automatic focusadjustment is obtained, and then automatic focus adjustment is preformedbased on the parameter thus obtained. Although in the flowchart shown inFIG. 3A, the automatic focus adjustment processing for taking a clearimage of the EP is executed in the step 304, there can be adopted avariation such as setting the AF for taking a clear image of the AP inthe same manner prior to the step 303, thereby executing the automaticfocus adjusting processing using the AF prior to the AP imaging (thesame applies to the AST, ABCC described later).

In the step 305, based on the control and processing of the processingcontrol section 115, the imaging position is moved to the AST using thebeam shift, thus taking an image, a parameter for automatic astigmatismadjustment (astigmatism correction) is obtained, and then automaticastigmatism adjustment is preformed based on the parameter thusobtained.

Then, in the step 306, based on the control and processing of theprocessing control section 115, the imaging position is moved to theABCC using the beam shift, thus taking an image, a parameter forautomatic brightness/contrast adjustment is obtained, and then automaticbrightness/contrast adjustment is preformed based on the parameter thusobtained (in order to obtain a clear image with an appropriatebrightness and contrast when taking the image of the EP, by adjustingthe parameters such as the voltage value of the photomultiplier in thesecondary-electron detector 109, the adjustment is executed so that thepart with the highest image signal and the part with the lowest imagesignal show the full-contrast or the contrast close to thefull-contrast).

Lastly, in the step 307, the imaging point is moved to the EP using thebeam shift, and thus taking the image, and the dimension measurement ofthe pattern is performed with the measurement conditions thusdetermined.

FIG. 3B shows an example of the template positions of the EP 309, the AP310, the AF 311, the AST 312, and the ABCC 313 on the beam shiftallowable area from the EP with dotted frames. It should be noted thatthere can be variations in the steps 303, 304, 305, and 306 such aseliminating some or all of these steps, arbitrarily changing the orderof the steps 303, 304, 305, and 306, or overlapping the coordinates ofsome of the AP, the AF, the AST, and the ABCC (e.g., the automatic focusadjustment and the automatic astigmatism adjustment are executed at thesame position) according to the cases.

2. Flow of Automatic Recipe Creation Processing

The present invention relates to a method of automatically creating therecipe of the SEM. In order to achieve shortening of hours for creatingthe recipe and the reduction of incidence of the operator, improvementin the ratio of automation is essential, and to that end, it is achallenge that how automatically and quickly the recipe, which has aperformance equivalent or superior to that of the recipe manuallycreated by the operator, can be created. The processing flow accordingto the present invention will be explained using FIG. 4.

2.1. Data Input

Firstly, the coordinates of the EPs and the design data of thesemiconductor circuit pattern are input (steps 401, 402, respectively).As the coordinates of the EPs, there are input the coordinates of hotspots (critical points) detected based on the result of, for example, anexposure simulation executed by an Electronic Design Automation (EDA)tool. Alternatively, in some cases, the coordinates of the EPs are inputon a judgment of the user itself (taking the information of the EDA toolinto consideration, if necessary). Further, in some cases, the attributeinformation of the EPs can also be obtained, or it is possible to inputthe attribute information if necessary (step 403). As the attributeinformation, a candidate of a possible defect at the EP (hereinafterreferred to as a candidate defect) and so on can be cited. The candidatedefect denotes a defect mode in which the patterns can be linked witheach other at the EP (bridging), or the pattern can be narrowed orbroken (necking), for example. It is possible to input the candidatedefect with the highest possibility of occurrence referring to theanalysis result by, for example, EDA tool, or to input the candidatedefect the user wants particularly to avoid. It is possible to input aplurality of candidate defects for one of the EPs.

2.2. Dimension Measurement/MP Estimation Step

Subsequently, in the measurement recipe creation section 406, thedimension measurement type and the coordinates of the MP are estimatedfor each of the EPs (step 407). In order to create the dimensionmeasurement cursor in the step 408 described later, it is required toknow where the pattern to be measured exists in the EP, and what kind ofmeasurement should be executed on the pattern to be measured. Regardingthe estimation of the MP coordinates described above, although there aresome cases in which the EP coordinates (the center coordinates of the EParea) match with the MP coordinates, there are also the cases in whichthey do not match with each other, or the cases in which two or more MPsexist in the EP. Further, even if the MP coordinates are provided by theinput from the user, there is a possibility that the coordinate valuesinclude an error. Therefore, based on the coordinate data of the EP andthe design data of the circuit pattern including the EP, the MPcoordinates are estimated in the computer. Further, the dimensionmeasurement types denote the variations of measurement at the MP, and asspecific examples of the dimension measurement types, there are citedmeasurement of the line width of the line pattern, measurement of thegap between the line patterns, measurement of the amount of recession ofthe line end section, measurement of the diameter of the contact hole,measurement of the optical proximity correction (OPC) shape, and so on.Further, it is possible to include the information of a region to bemeasured such as the regions in the wiring area distance of which ismeasured in the dimension measurement type besides the category such asmeasurement of the line width. Further, it is also possible to includethe information of a measurement direction such as a direction an amountof recession in which is measured in the measurement of “an amount ofrecession” in the dimension measurement type.

In the determination of the dimension measurement type/MP, taking the EPattribute information such as the candidate defects input in the step403 into consideration, so as to reflect the managing intention of theuser on the pattern shape at the EP, how the SEM, the measurement tool,measures the MP (i.e., the dimension measurement type) can bedetermined. As the estimation rule for estimating the dimensionmeasurement type/MP in the computer, the default values related to theestimation rule and the processing parameters for the estimationprepared inside the system can be input for use if necessary (step 404).Further, the required specifications (e.g., specific requirements like“measurement of the region with as small design dimension as possible ispreferable” or “measurement of a specific region is preferable withrespect to a specific pattern”) of the user regarding the dimensionmeasurement type/MP are input if necessary, thus making it possible tocreate the estimation rule taking the required specifications intoconsideration (step 405).

2.3. Dimension Measurement Cursor Creation/Dimension Measurement MethodDetermination Step

Subsequently, in the step 408, creation of the dimension measurementcursor, and selection or determination of the dimension measurementmethod are performed. In the creation of the dimension measurementcursor, the position and the shape of the dimension measurement cursorare determined on the design data (the dimension measurement cursor hasthe coordinates linking with the design data). Further, thedetermination of the dimension measurement method correspondsspecifically to determination of the dimension measurement algorithm andthe dimension measurement parameters. The selection or setting of thedimension measurement method is executed taking the information such asa dimension measurement type, or a shape or a direction of a patterncontour of the pattern to be measured into consideration if necessary.

2.4. SEM Imaging Conditions Determination Step

Subsequently, in the step 409, the imaging conditions of the SEM at theEP are determined. The SEM imaging conditions include at least thescanning direction of the electron beam. Although the raster scan iscommon in the two-dimensional scanning of the electron beam for creatingthe SEM image, the obtained SEM image is different between, for example,the case in which the scanning of the two-dimensional area is performedby executing continuous electron beam scanning in the x direction aplurality of times while shifting the scanning position discretely inthe y direction, and the case in which the scanning of thetwo-dimensional area is performed by executing continuous electron beamscanning in the y direction a plurality of times while shifting thescanning position discretely in the x direction. Therefore, it iseffective to automatically setting the scanning method with which theSEM image advantageous to the measurement taking the measurement regionand the measurement direction in the EP into consideration. The scanningmethod is not limited to the scanning in the direction parallel to the xor y direction, but can have variations such as scanning in an obliquedirection or scanning in the direction varying in accordance with theposition in the EP.

2.5. EP Imaging Range/Coordinate Optimization Step

Subsequently, in the step 410, optimization of the imaging range and thecoordinates of the EP are executed. The imaging range should bedetermined from the viewpoint that the measurement of the desired regionin the MP is realized with appropriate measurement accuracy in additionto the viewpoint of the range the user wants to check. Therefore, it isnecessary to set the imaging range so as to include at least the rangeof the dimension measurement cursor required from the viewpoint ofmeasurement accuracy. Further, it is possible to change the coordinatesof the EP provided by the user if necessary. The optimization of the EPcoordinates includes principally three items, (a) changing thecoordinates of the EP and the imaging range, (b) merging a plurality ofview fields of the EPs to newly set a single EP, and (c) dividing one EPto set a plurality of EPs, and any combinations of these items. Specificexamples of the contents of the processing and the advantages of therespective cases will be described below.

In the case of (a), if the position of the MP (or the imaging areaincluding the dimension measurement cursor necessary for measurement) isfound, it becomes possible to determine whether or not the center of theEP is shifted from the MP, and if it is shifted, it becomes possible totake the image of the MP at roughly the center of the view field of theEP by matching the view field of the EP with the center of the MP.Further, for example, it is possible to adjust the imaging range so thatthe range of the dimension measurement cursor is sufficiently includedin the view field of the EP with respect to the imaging misalignment.

In the case of (b), when imaging/measuring dense continuous patterns insequence, for example, in some cases, the imaging ranges setrespectively to the patterns overlap with each other. In this case,there is a possibility that when taking an image of a certain EP, thecontamination is caused in the measurement area included in another EP,thus degrading the measurement accuracy. Therefore, by resetting the EParea so that the patterns included in the respective EPs arecollectively included in a single view field, the contamination in themeasurement area described above can be prevented from occurring. Whenmerging the EPs, the determination thereof can be made taking whether ornot the dimension of the view field or the imaging magnification of theEP obtained by merging is within a predetermined dimension (since themeasurement accuracy is generally lowered with the lower magnification)and whether or not the SEM imaging conditions (e.g., scanning directionof the electron beam) of the EPs to be merged match each other intoconsideration.

In the case of (c), if a plurality of MPs are included in the EP, andfurther, the directions of the patterns to be measured in the respectiveMPs are different from each other, and therefore, the SEM imagingconditions (e.g., the scanning direction of the electron beam) isrequired to be different between the MPs, it is effective to separatethe MPs from each other as the EPs, thus taking images with the SEMimaging conditions different from each other. Further, in the case inwhich a number of MPs are included in the EP, and the MP is locatedclosest to the edge of the view field of the EP, there is a possibilitythat a part of the measurement area of the MP runs off the view fielddue to the view field misalignment caused when taking the image of theEP. In such a case, division of the EP is effective.

2.6. Imaging Sequence Determination Step

Subsequently, in the imaging recipe creation section, the imaging recipefor taking the image of each of the EPs is created. Specifically, thedetermination of the imaging sequence including the setting of some orall of the adjustment points, the AP, the AF, the AST, the ABCCexplained using FIGS. 3A and 3B is executed (step 412), and each of thetemplates of the adjustment points and the EP is registered in therecipe as the registered template if necessary (step 413). Further,based on the EP coordinates, the dimension measurement type, and the SEMimaging conditions determined in the measurement recipe creation section406, the imaging order of the EPs is determined.

2.7. Imaging/Measurement Recipe Creation Step

In the step 414, the various parameters (the dimension measurementcursor, the dimension measurement method, the imaging sequence, theregistered templates, and so on) determined in the measurement recipecreation section 406 and the imaging recipe creation section 411 arestored in the recipe (also referred to as the imaging/measurementrecipe). Although in the embodiment, the items to be set in the imagingrecipe and the measurement recipe, and the estimation procedures areseparately explained, as described above, it is possible to manage thesetting items designated by each of the recipes as a desiredcombination. By performing the processing based on the resign data,there is no need for taking an SEM image of a real wafer when creatingthe recipe on and before the step 414, and therefore, the operation canbe carried out online, which leads to an improvement of the operationrate of the apparatus.

2.8. EP Imaging Step

Subsequently, in an imaging/measurement section 416, theimaging/measurement using a real wafer is performed. Firstly, the waferis set in the SEM device (step 415), and the image of the EP is takenbased on the recipe (step 417).

2.9. Dimension Measurement Cursor Disposition/Correction Step

Since the positional relationship between the SEM image of the EP andthe corresponding design data can be obtained by actually taking the SEMimage of the EP and matching the SEM image of the EP and thecorresponding design data with each other, and the positionalrelationship between the dimension measurement cursor and the SEM imagecan also be obtained at the same time, the dimension measurement cursorcan automatically be disposed on the SEM image (step 418). It should benoted that when actually imaging/measuring the EPs using the recipecreated in a waferless condition based on the design data, the misfit ofthe shape between the pattern actually formed on the wafer and thepattern on the design data might be a problem. Therefore, afterautomatically disposing the dimension measurement cursor on the SEMimage of the EP in the step 418, the shape misfit between the pattern inthe SEM image and the pattern in the design data is calculated, thuscorrecting the position or the shape dimension measurement cursor basedon the shape misfit information (step 419). According to the presentprocessing, it becomes possible to correctly measuring the dimensioneven if the shape and the position of the actual pattern are differentfrom those of the design data to a certain extent.

2.10. Dimension Measurement Method Changing Step

Similarly to the position and the shape of the dimension measurementcursor described above, some of the items designated by the recipecannot accurately be determined only with the design data. In the case,for example, of measuring the amount of recession of the line endsection, although it is required to accurately detect the position ofthe line end section, in some cases, the corner sections of the patternare rounded with respect to the mask pattern due to the resolution limitof the lithography. In the case in which there is a straight sectionwith an enough length, it is possible to use an algorithm for detectingthe line end section by applying the straight section. In the case inwhich a rounded section is dominant, it is possible to use an algorithmfor detecting the line end section by applying the rounded section.However, there is a limit in estimating the extent of rounding of theline end section based only on the design data. Further, the extent ofrounding can be varied in accordance with the variation in themanufacturing process. In order to solve such a problem, a part of orthe whole information of the dimension measurement method is changedbased on the SEM image after obtaining the real SEM image if necessary(step 420). The steps 419, 420 are mechanisms for making the recipe,which is created based on the design data in the waferless condition,appropriately applicable to the real patterns. Although these steps areexecuted after the SEM imaging, these are correction of the settingitems once determined offline, and do not require substantial processingtime. Most of the processing is executed offline, and therefore, has nosignificant influence on the throughput of the SEM imaging.

2.11. Dimension Measurement Step

Using the dimension measurement cursor and dimension measurement methoddetermined finally, the dimension measurement is performed using the SEMimage at the EP (step 421). Further, if necessary, success and failureof the measurement is measured (step 422), and based on the result ofthe success and failure measurement, the recipe creation rule is changedin the step 427 described later if necessary. The determination of thesuccess and failure of the measurement can be analyzed and managed withthe categorized causes of failure such as (a) failure in imaging of (b)failure in measurement, further (a) can be categorized in further detailsuch as (a1) imaging misalignment caused by failure in addressing or(a2) blur of image caused by defocusing, and (b) can be categorized infurther detail such as (b1) failure in dimension measurement type/MPestimation, (b2) misalignment of dimension measurement cursor, (b3)improper shape of dimension measurement cursor, or (b4) improperdimension measurement method.

2.12. Measurement Result Analysis/Recipe Creation Rule Optimization Step

Subsequently, in the measurement result analysis/recipe creation ruleoptimization section 423, based on the measurement result obtained inthe step 421, the facture of the pattern is analyzed (step 424), and byperforming the correction of the shape of the mask pattern or themodification of the semiconductor manufacturing process conditions, ifnecessary, a high yield ratio can be achieved (step 425).

Further, the recipe and the imaging/measurement result are analyzed(step 426) based on the recipe, the recipe creation rule, thedetermination result of the success and failure of theimaging/measurement and the information such as the cause of the failureobtained in the step 422 in the case of the failure in theimaging/measurement, and modification of the recipe creation rule isperformed (step 427) if necessary.

At least one combination of the coordinates of the EP, the design data,the dimension measurement type/MP, the creation rule of the recipe, therecipe thus created, the image taken by the actual imaging sequence, themeasurement result, and success and failure of one of the imaging andmeasurement is managed in a database while being associated with eachother, thus making it possible to share the recipe among two or more SEMdevices through a network or the like. In addition to the advantage thatthe necessity of creation of the recipe by every device can beeliminated, since the result data including successful cases and failedcases in the imaging/measurement obtained from a plurality of devicescan be shared, it is possible to collect a lot of result data quickly,and if a problem exists in the recipe creation rule, for example, ameasure against the problem can quickly be taken.

3. Detailed Explanations

Hereinafter, areas for which detailed explanations are necessary areextracted from the processing flow shown in FIG. 4, and supplementaryexplanations therefor will be presented.

3.1. Details of Dimension Measurement Type/Dimension MeasurementCursor/SEM Imaging Conditions

The dimension measurement type, the dimension measurement cursor, andthe SEM imaging conditions described in the steps 407 through 409 willbe explained in detail with reference to FIGS. 6A through 6P. In FIGS.6A through 6P, 601, 604, 608, 612, 615, 621, 624, 628, 632, 645, 648,651, and 656 define the imaging ranges of the EP. As examples of thedimension measurement types, FIG. 6A shows the line width measurement ofa line pattern 602, FIG. 6B shows the space measurement between linepatterns 604 and 606, FIG. 6C shows the gap measurement between a lineend section of a line pattern 609 and a line pattern 610, FIG. 6D showsthe recession amount measurement (including expansion amountmeasurement) of a line end section of a line pattern 613, FIGS. 6E and6F show diameter measurement of contact holes 616, 622, respectively,FIG. 6G shows the major axis/minor axis measurement, FIG. 6H shows thegap measurement between line patterns 629 and 630, FIG. 6I is the shapemeasurement of a pattern 633 (specifically, the shape of the cornersection indicated by a dotted frame 634). In the drawings, dotted frames603A, 603B, 607A, 607B, 611A, 611B, 614, 617A, 617B, 618A, 618B, 619A,619B, 620A, 620B, 623A, 623B, 626A, 626B, 627A, 627B, 631A, 631B, 634indicate the dimension measurement cursor. Further, the arrowsillustrated together with the dotted frames indicate the places on whichthe dimension measurement is executed.

For example, in order to measure the line width, it is required toaccurately and stably measure the positions of the right and left edgesof the line. Therefore, an area (an area of the dimension measurementcursor, 603A or 603B in FIG. 6A) with a predetermined dimensionincluding the edge is set on each of the right and the left edges, and acumulative profile less subject to the image noise or the line edgeroughness is obtained by accumulating the SEM signal in the area in theline direction, and the edge position is detected using the profile. Thereference numeral 637 in FIG. 6K shows the SEM signal profilecorresponding to the line between α and β shown in FIG. 6A. In order toimprove the S/N of the SEM signal profile 637 described above, it isalso possible to use a profile obtained by averaging the SEM signal inthe y direction in a length corresponding to, for example, the range(643) of the dimension measurement cursor.

In the SEM signal profile 637, the peak positions 638 of the right andleft white bands are detected, and the distance between the peakpositions 638 is measured as the line width. Although in the presentembodiment, the distance between the peaks of the SEM signal profile isdefined as the line width, there can be variations in the positions inthe profile between which the distance is measured as the line width.For example, it is possible to obtain positions in the right and leftwhite bands having a brightness value of X % of the difference betweenthe peak brightness value and the brightness value of the substrate, andthe distance between the positions thus obtained is measured (theparameter such as X % in the dimension measurement algorithm representedby the measurement described above is called a dimension measurementparameter). Examples of position or dimension parameters for determiningthe position and the shape of the dimension measurement cursor describedabove are shown in FIG. 6L, which is an enlarged diagram of FIG. 6A. Asthe parameters, there are cited arrangement positions of the dimensionmeasurement cursors 640A and 640B, outside profile reference ranges641A, 641B of the dimension measurement cursors 640A, 640B, disposedoutside the line pattern 639, inside profile reference ranges 642A, 642Bdisposed inside the line pattern 639, and a profile accumulation ranges643A, 643B. Thus, the line width 644 is accurately measured. Thecoordinates of the MP can be defined as, for example, the midpoint (orthe midpoint of the line width 644) of the dimension measurement cursors640A and 640B.

Further, in some cases, the dimension measurement cursors are set as apair of dimension measurement cursors such as the pair of dimensionmeasurement cursors 603A and 603B shown in FIG. 6A, and in other cases,the dimension measurement cursor is set as a single dimensionmeasurement cursor such as the dimension measurement cursor 614 shown inFIG. 6D. Since in the case of FIG. 6D, the amount of recession of theline end section of the line pattern 613 is measured, the dimensionmeasurement cursor is set so that the position of the line end sectioncan accurately obtained by the SEM signal analysis inside the dimensionmeasurement cursor 614.

In FIG. 6E, in order to measure the average hole diameter, the pairs ofdimension measurement cursors are disposed at several positions in thecircumferential area of the hole 616 (in the example shown in thedrawing, four pairs of positions of 617A and 617B, 618A and 618B, 619Aand 619B, and 620A and 620B), and the process such as averaging thediameter values thus measured is performed. It is also possible tomeasure the diameter at a pair of positions of the hole 622 with thedimension measurement cursors 623A, 623B as shown in FIG. 6F, and usethe diameter thus measured as the representative value of the holediameter.

In FIG. 6G, the minor axis of the pattern 625 is measured with thedimension measurement cursors 626A, 626B, and the major axis is measuredwith the dimension measurement cursors 627A, 627B, respectively. In thecase of defining that the center of the dimension measurement cursors asthe coordinates of the MP, the MP coordinates of the minor axismeasurement and the major axis measurement are identical to each other.As described above, it is possible to set a plurality of dimensionmeasurement types with respect to a single MP coordinate.

In FIG. 6I, in order to perform the evaluation of the facture of thecontour of a two-dimensional pattern, dense shape gap vectors 636between the pattern 633 on the SEM image and the design data 635displayed in an overlaying manner on the pattern on the SEM image areobtained as shown in FIG. 6J, the enlarged view of the area 634indicated in FIG. 6I. As described above, the measurement of a pluralitypositions is also possible instead of measurement of one of a pluralityof positions. Further, there can be cited a measuring method ofquantizing the degree of rounding of a corner, for example, based on themeasurement values of the plurality of positions, and outputting thequantized value as one of evaluation values. Further, the measurementvalue is not limited to the distance between desired two regions of thepatterns on the SEM image, but it is possible to use the misfit amountbetween the design data and the pattern on the SEM image at a desiredregion as the measurement value, for example, as described above.

As described above, the difference in the type of the pattern and theregion on which the cursor is disposed is categorized as the dimensionmeasurement type.

Further, it is possible to include the information of the measurementdirection in the dimension measurement type. FIG. 6M shows an example ofmeasuring the line width of the line pattern 646 extending in the ydirection, namely the dimension in the x direction, FIG. 6N shows anexample of measuring the line width of the line pattern 649 extending inthe x direction, namely the dimension in the y direction. Suchinformation of the measurement direction becomes the informationnecessary for determining the SEM imaging conditions in the step 409shown in FIG. 4 described later. A determination method of the scanningdirection of the electron beam, which is one of the SEM imagingconditions, will be explained as an example. Since in FIG. 6M thedimension in the x direction is measured, it is desirable to scan theelectron beam continuously in the x direction. Therefore, asschematically shown in the drawing, it is possible to obtain the imageby executing the continuous electron beam scan 647 in the x direction aplurality of times while shifting the scan line discretely in the ydirection (in the drawing, the number of times of shifting isschematically set to four times). Since in FIG. 6N the dimension in they direction is measured, similarly, in this case, it is possible toobtain the image by executing the continuous electron beam scan 650 inthe y direction a plurality of times while shifting the scan linediscretely in the x direction. As described above, owing to theinformation of the measurement direction, appropriate SEM imagingconditions can be determined. The reference numerals 662A, 662B is FIG.6M, and 663A, 663B in FIG. 6N respectively denote the dimensionmeasurement cursors.

3.2. Details of Dimension Measurement Type Estimation/MP Estimation

The dimension measurement type estimation/MP estimation described in thestep 407 will be explained in detail with reference to FIG. 5. In orderto automatically create the dimension measurement cursor, it isnecessary to know the dimension measurement type/MP in the EP. In otherwords, the dimension measurement cursor can hardly be set withoutunderstanding what deformation of the pattern possibly occurs at whichplace, and what dimensional value needs to be measured/controlled withrespect to the deformation. Further, it is not easy for the user tomanually designate all of such dimension measurement types. Therefore,the dimension measurement types/MP are estimated inside the computerbased on the coordinate data of the EPs and the design data of thecircuit pattern including the EPs, and the dimension measurement cursoris created based on the dimension measurement types/MP thus estimated.Firstly, the EP is selected in the step 501 shown in FIG. 5. The designdata corresponding to the area including the EP is input in the step508, and the candidate of the dimension measurement type/MP is refinedin the step 502. Here, if the candidate of the dimension measurementtype/MP is determined (in the case in which the determination of the“DIMENSION MEASUREMENT TYPE/MP DETERMINED?” in step 503 is Yes), theprocess proceeds to step 504. If the candidate of the dimensionmeasurement type/MP is not determined (in the case in which thedetermination of the “DIMENSION MEASUREMENT TYPE/MP DETERMINED?” in step503 is No), warning is sent to the user via the GUI or the like (step514). The user can change the estimation rule of the dimensionmeasurement type/MP referring to the example in which the dimensionmeasurement type has not been determined appropriately.

FIG. 7A shows patterns 702, 703 on the SEM image included in the viewfield 701 of the EP, as an example. FIG. 7B shows the design datacorresponding to the EP, and the patterns on the design datacorresponding to the patterns 702, 703 are 704, 705, respectively. Theexamples of the candidate of the MP coordinate estimated from the designdata are cited as 708, 710, 712, 714, 716, and 718 in FIGS. 7D through7G, respectively. From the viewpoint of the dimension measurement type,the MP 708 corresponds to the measurement of the line width of the linepattern in the x direction at the region measured by the dimensionmeasurement cursors 709A, 709B, the MP 710 corresponds to themeasurement of the line width of the line pattern in the x direction atthe region measured by the dimension measurement cursors 711A, 711B, theMP 712 corresponds to the measurement of the amount of recession in theline end section in the y direction at the region measured by thedimension measurement cursor 713, the MP 714 corresponds to themeasurement of the amount of recession in the line end section in the ydirection at the region measured by the dimension measurement cursor715, the MP 716 corresponds to the measurement of the gap between theline patterns at the region measured by the dimension measurementcursors 717A, 717B, and the MP 718 corresponds to the measurement (themeasurement of the rounding of the corner or the like) of the OPC shapeat the region measured by the dimension measurement cursor 719. Asdescribed above, a plurality of candidates of the dimension measurementtype/MP exists in the single EP, and the dimension measurement type/MP,which the user actually wants to measure, may be one of the candidatesdescribed above, or may be a combination of the candidates. Therefore,in the estimation of the dimension measurement type/MP to be actuallymeasured, at each of the pattern regions included in the circuit designpattern including the EPs, attribute information composed of at leastone combination of a candidate of the dimension measurement type, acandidate of a possible defect, a circuit attribute, easiness ofdeformation, measurement dimension on the design data, and the distancefrom the center of the EP is calculated, and the candidate of thedimension measurement type/MP at the EP is extracted along theestimation rule based on the attribute information. By taking aplurality of pieces of attribute information into consideration, theautomatic estimation of the dimension measurement type/MP with highaccuracy becomes possible.

Further, as described above, the estimation rule of the dimensionmeasurement type/MP can be determined taking the attribute 509(corresponding to 403 shown in FIG. 4) of the EP, the default values 510(corresponding to 404 shown in FIG. 4), and the user requiredspecification 511 (corresponding to 405 shown in FIG. 4) intoconsideration if necessary. Further, as a mechanism for reflecting thedifference in the setting criteria of the dimension measurement type/MPbetween the users, it is possible to input the dimension measurementtype/MP estimation rule designated by the user (step 512). It should benoted that the creation of the estimation rule is generally a difficultwork for the user. Therefore, as the mechanism for easily performing theuser customization, it is possible that, in response to the userperforming at least one combination teaching of the EP and the positionof the MP in the EP, or a combination teaching of the EP and thedimension measurement type in the EP (step 513), the estimation rule isoptimized inside the system based on the teaching, thus the generalestimation rule can automatically be created.

When the dimension measurement type/MP is determined, the dimensionmeasurement cursor creation/dimension measurement method determinationis performed in the step 504, and the determination of the SEM imagingconditions is performed in the step 505 if necessary. The processing ofthe steps 501 through 505 are executed repeatedly with respect to all ofthe EPs to be imaged (determination of the termination is made in thestep 506), then in the step 507, optimization of the EP imagingrange/coordination is performed (corresponding to the step 410).

Incidentally, the estimation of the dimension measurement type/MP or thecreation of the dimension measurement cursor is effectively performedbased on the pattern similar to the shape of the real pattern formed onthe wafer as much as possible. Therefore, it is possible to perform theestimation or the creation using the patterns 706, 707 (hereinafterreferred to as modified design data) obtained by modifying the patterns704, 705 on the design data shown in FIG. 7. As the method of generatingthe modified design data, there can be cited a method of generating themodified design data using litho-simulator on the design data, and amethod of generating the modified design data by the shape modificationbriefly simulating the litho-simulator. The modified design data 706,707 in the drawing is an example of rounding the corner sections of thedesign data 704, 705 assuming that the corner sections of the patternare rounded due to the resolution limit of the lithography.

3.3. Details of EP Imaging Range/Coordinate Optimization

A specific example of the EP imaging range/coordinate optimizationdescribed in the step 410 will be explained with reference to FIG. 8.FIG. 8A shows an example in which the user wants to measure the linewidth of each of the six line patterns 802 through 807. The MPs disposedon the six line patterns are 808 through 813, respectively. FIG. 8Bshows the EPs 814 through 819 having the view fields set correspondinglyto the centers of the MPs so that the measurement in each of the linepatterns becomes possible. However, if the EPs are set as shown in FIG.8B, the imaging ranges of the EPs overlap with each other, and whentaking the image of one of the EPs, contamination is caused in themeasurement area included in another of the EPs, there is a possibilityof degrading the measurement accuracy. Therefore, it is possible tooptimize the imaging range of the EP as illustrated as the EPs 820, 821shown in FIG. 8C. In the present embodiment, the MPs 808 through 810 canbe measured using the EP 820, and the MPs 811 through 813 can bemeasured using the EP 821, and moreover, there is no overlapping areabetween the EPs 820, 821. Further, the number of times of imaging canalso be reduced from six in the case with the EPs 814 through 819 to twoin the case with the EPs 820, 821. Incidentally, from the viewpoint ofthe number of times of imaging, it is possible to include entire area801 in one EP. However, in such a case, there is a possibility ofdegrading the measurement accuracy because the magnification is lowered.Therefore, it is necessary to set the EP imaging range or the EPcoordinates taking the overlapping of the ranges, the number of times ofimaging, the measurement accuracy, and so on into consideration, andachieving a balance therebetween.

Further, in the optimization of the EP imaging range/coordinates, it isnecessary to take the SEM image conditions in the EP into consideration.FIGS. 8D through 8F show examples of optimizing the EP imagingrange/coordinates based on the scanning direction of the electron beamout of the SEM imaging conditions. In FIG. 8D, there are disposed threeMPs 825, 828, and 830 on the design data 823 and 824, and the EPs 832,833, and 834 including the respective MPs are set as an initialcondition. Out of the three MPs, the MPs 825, 828 correspond to the linewidth measurement in the x direction, and as shown in FIG. 6M, it isdesirable to perform the continuous scan in the x direction, and thediscrete scan in the y direction. In contrast, the MP 830 corresponds tothe line width measurement in the y direction, and as shown in FIG. 6N,it is desirable to perform the continuous scan in the y direction, andthe discrete scan in the x direction. Therefore, it is necessary toperform the SEM imaging on the MPs 825, 828, and the MP 830 withdifferent imaging conditions, and therefore, it is not allowed to mergethe both parties into the same EP. Therefore, for example, as shown inFIG. 8E, it is possible to merge the MP 825 and MP828 into a single EP835, and to take the image of the MP 830 as a single EP 836. Incontrast, as shown in FIG. 8F, in the case in which the MP 825corresponds to a single EP 837, and the EP 838 into which the MPs 828,830 are merged is provided in the initial condition, it is possible toseparate the both MPs to two EPs based on the determination criteriadescribed above. As describe above, for the optimization of the imagingrange of the EP, and integration/separation of the EP, it is effectiveto use the information of the dimension measurement type, MPs, and thedimension measurement cursors (826A, 826B, 829A, 829B, 831A, and 831B).

Incidentally, it is necessary for the imaging range to appropriatelyinclude the measurement area (the area of the SEM image required toperform the measurement), and it is preferable that the measurement areais included in the view field even if there is some imagingmisalignment. An explanation will be presented exemplifying FIGS. 6O and6P. FIG. 6O shows an example of the line width measurement of the linepattern 652, and the dimension measurement cursors are denoted as 653A,653B. Regarding the setting of the imaging range of the EP, it isrequired to include at least the dimension measurement cursors 653A,653B, and in the case in which there is a possibility that the viewfield shift is caused in the x direction with a distance 654, it isdesirable that the imaging range 655 includes the measurement area evenif the imaging range 651 is shifted as much as the distance 654 tobecome the imaging range 655. In this example, no problem occurs withrespect to the amount of view field shift of 654. On the other hand,FIG. 6P shows an example of measurement of the gap between the patterns657 and 658. Although the dimension measurement cursors 659A, 659B areincluded in the imaging range 656 similarly to the example of FIG. 6O,in the case in which the imaging range is shifted to 661 in accordancewith the amount of position shift 660 identical to the amount of theposition shift 654 described above, a part of the dimension measurementcursor runs off the view field. As described above, it is effective todetermine the imaging range based on the range of the dimensionmeasurement cursor and the expected value of the view field shift.

3.4. Details of Imaging Sequence Determination

In the imaging sequence determination described in the step 412, aspecific example of determination of the imaging order of the EPs willbe explained with reference to FIGS. 11A through 11E. FIG. 11A shows anexample in which eight EPs exist in an area with low magnification, andthe eight EPs are denoted as EP[1] through EP[8], respectively. In theview field of each of the EP[1], EP[3], EP[5], and EP[7], there areincluded three line patterns extending in the x direction, and these EPsare collectively called EP group 1. In the view field of each of theEP[2], EP[4], EP[6], and EP[8], there are included three line patternsextending in the y direction, and these EPs are collectively called EPgroup 2. The EPs belonging to the EP group 1 correspond to the linewidth measurement in the y direction, and the scanning direction of theelectron beam as illustrated with the arrows 650 shown in FIG. 6N ispreferable. In contrast, the EPs belonging to the EP group 2 correspondto the line width measurement in the x direction, and the scanningdirection of the electron beam as illustrated with the arrows 647 shownin FIG. 6M is preferable. Therefore, in the case in which the EPbelonging to the EP group 2 is imaged after the EP belonging to the EPgroup 1 has been imaged, or the EP belonging to the EP group 1 is imagedafter the EP belonging to the EP group 2 has been imaged, it is requiredto execute a rotation of the view field or the beam scan. In the lightof the above, optimization of the imaging order will be considered. Asshown in FIG. 11B, the initial imaging order (input by the user, forexample) is sequentially from the EP[1] to the EP[8]. In contrast, withintent to reduce the number of rotation, for example, as shown in FIG.11C, starting with the imaging of the EP group 1, the order will beEP[1]→EP[3]→EP[5]→EP[7]→EP[2]→EP[4]→EP[6]→EP[8]. It should be noted thatin order to reduce the total distance of view field movement between theEPs thereby improving the throughput, as shown in FIG. 11D, the orderwill be EP[1]→EP[5]→EP[7]→EP[3]→EP[2]→EP[6]→EP[8]→EP[4] (because thedistance between the EP[1] and EP[5] is shorter than the distancebetween EP[1] and EP[3]). It should be noted that if the time requiredfor rotation is extremely shorter than the time required for the viewfield movement between the EPs, it is possible to adopt the order shownin FIG. 11B giving weight to the reduction of view field movement.Further, if the time required for the rotation and the time required forview field movement are equivalent to each other, the imaging ordershown in FIG. 11E can also be adopted taking the both into consideration(the number of times of rotation is smaller than that shown in FIG. 11B,and the view field movement distance is shorter than that shown in FIG.11D). As described above, the imaging order of the EPs are determinedbased on the EP coordinates or the SEM imaging conditions including atleast the scanning direction of the electron beam in the EPs.

3.5. Details of Dimension Measurement Cursor Correction

A specific example of the dimension measurement cursor correctiondescribed in the step 419 will be explained with reference to FIGS. 9Athrough 9K. The present drawings related to the examples for correcting(A) the distance 906 between the dimension measurement cursor, (B) theoutside profile reference ranges 903A, 903B located outside the linepattern 901 based on the design data, and (C) the arrangement positionsof the overall dimension measurement cursor among the various positionand dimension parameters for determining the dimension measurementcursor, and other dimension parameters can also be corrected in asubstantially the same manner. Further, in order to achieve consistencyin the measurement values with the EPs, it is possible to performsetting so as not to perform correction of some or all of the positionand dimension parameters (if, for example, the profile accumulationrange 905A, 905B become different between the EPs, there is apossibility that the measurement become unable to be compared to eachother.

(A) Correction of Distance Between the Dimension Measurement Cursors

FIG. 9A shows the dimension measurement cursors 902A, 902B disposed onthe design data 901 in the step 408 shown in FIG. 4. The inside of eachof the dimension measurement cursors 902A, 902B is divided into tworanges, namely an outside profile reference range 903A, 903B locatedoutside the line pattern 901 based on the design data and an insideprofile reference range 905A, 904B located inside the line pattern 901based on the design data. The object is to measure the line width in thex direction of the line pattern 907 observed with the SEM, and shown inFIG. 9B. Firstly, as shown in FIG. 9C, matching of the pattern 907 onthe SEM image and the design data 901 is performed, and as shown in FIG.9D, the dimension measurement cursors 902A, 902B are disposed on the SEMimage. Here, the pattern 907 on the SEM image has a line width extendedlargely (in the drawing, it is extended to be the widths 908A, 908Blarger than the design data 901) compared to the design data 901, thepositions of the dimension measurement cursors arranged assuming theline width on the design data are shifted from the edge positions of thepattern on the SEM image. Therefore, as shown in FIG. 9E, it is possibleto successfully measure the line width by shifting the position of thedimension measurement cursors in accordance with the edge positions (thedistance 906 between the dimension measurement cursors is increased to909).

(B) Correction of Outside Profile Reference Range Located Outside thePattern

In FIG. 9E, reference numeral 910 denotes the SEM signal profilecorresponding to the line traversing the line pattern 907, and extendingbetween α and β. In the line width measurement, there is used analgorithm of obtaining, for example, the positions each having thebrightness value of X % of the difference between the peak brightnessvalue and the brightness value of the substrate in the right and leftwhite bands (corresponding roughly to the right and left edges of theline pattern) of the SEM signal profile 910, and then measuring thedistance between the positions. In order to execute such various kindsof profile analysis, it is required for the measurement range (the rangeof the dimension measurement cursors) on which the analysis is executedto sufficiently include the protrusions of the white bands. Although theoutside profile reference ranges 903A, 903B located outside the linepattern 907 are set a little bit longer with a margin, in the real SEMsignal profile 910, the skirt section of the white band protrusions islonger than expected, and further, it has proved that the profile mustbe analyzed in the range the width 911A, 911B larger than expected. Onthis occasion, by correcting the outside profile reference ranges 903A,903B located outside the line pattern 907 so as to be extended to be912A, 912B as shown in FIG. 9F, it becomes possible to successfullymeasure the line width.

(C) Correction of Arrangement Positions of Overall Dimension MeasurementCursor

The reference numeral 912 shown in FIG. 9G denotes the design data ofthe upper layer pattern, and the reference numeral 913 denotes thedesign data of the lower layer pattern. The reference numerals 914A,914B denote the dimension measurement cursors, and are disposed so as tomeasure the line width 915 of the upper layer pattern 912 in the areawhere the upper layer pattern 912 and the lower layer pattern 913intersect with each other. This corresponds to the request, for example,that it is necessary to measure the line width in the active area of thegate exerting a significant influence on the apparatus characteristic.FIG. 9H shows the patterns 916, 917 on the SEM image correspondingrespectively to the patterns 912, 913 on the design data. Since thepattern 917 is located in the lower layer of the pattern 916 withrespect to the stacking direction of the pattern, there is cause ahidden part in the area where the both layers overlap with each other.FIG. 9I shows an example in which the pattern on the wafer and thedesign data are matched with each other, and the dimension measurementcursors 914A, 914B are arranged on the pattern. In the present example,the arrangement result of the dimension measurement cursors ispreferable. In contrast, FIG. 9J shows an example in which the upperlayer pattern 916 (corresponding to the design data 912) and the lowerlayer pattern 919 (corresponding to the design data 913) are shiftedfrom each other (the amount of shift is denoted as 918) due to a failureof the manufacturing process. FIG. 9J shows the result of matchingexecuted so that the pattern on the wafer and the design data match witheach other with respect to the upper layer pattern, and as a result,there arises a problem that the dimension measurement cursors aredisposed at the positions shifted a little from the positions where theupper layer pattern and the lower layer pattern overlap with each other,and on which the measurement is originally required to be executed.Therefore, as shown in FIG. 9K, by matching the lower layer pattern 921(corresponding to the pattern 913) with the pattern 919 on the SEM imageindependently from the upper layer pattern 912, and disposing thedimension measurement cursors 920A, 920B (corresponding to the dimensionmeasurement cursors 914A, 914B) in conjunction with the position of thelower layer pattern 921, the measurement on the desired place isrealized. As described above, it is required to dispose the dimensionmeasurement cursors appropriately based on the intent of the user on themeasurement.

3.6. Details of Change of Dimension Measurement Method

A specific example of the change of the dimension measurement methoddescribed in the step 420 will be explained with reference to FIG. 10.The dimension measurement method denotes specifically the dimensionmeasurement algorithm and the dimension measurement parameters. FIG. 10Ashows two patterns 1001, 1002 on the design data and the dimensionmeasurement cursors 1003A, 1003B for measuring the distance 1004 betweenthe two patterns described above. FIG. 10B shows a matching resultbetween the patterns 1005, 1006 on the SEM image and the design datadescribed above, and FIG. 10C is an enlarged view in the vicinity of thedimension measurement cursor 1003B. As an image processing algorithm fordetecting the end section of the pattern 1002 with good accuracy afterapplying the dimension measurement cursors, it is possible to adopt analgorithm of detecting the end section by applying the straight lines,providing the end section has enough straight line section. The five xmarks 1007 shown in FIG. 10C represent characteristic points of the endsection detected from the SEM image, and by applying straight lines tothe characteristic points, it becomes possible to stably detect the endsection with respect to the variation in the shape of the end section(the straight line 1008 is applied). Meanwhile, FIG. 10D shows anexample in which the corner sections of the patterns 1009, 1010(corresponding to the patterns 1005, 1006) are rounded significantly dueto the resolution limit of the lithography in the similar measurementexample, and FIG. 10E is an enlarged view in the vicinity of thedimension measurement cursor 1003B. In contrast to the straight lineapplication algorithm described above, in the case in which the roundedsection is dominant as the characteristic points 1011 in the endsection, an algorithm for detecting the end section by applying curvedline is effective (the curved line 1012 is applied). As described above,for example, in some cases, the degree of rounding in the end sectionscannot accurately estimated only with the design data. In order to solvesuch a problem, apart of or the whole information of the dimensionmeasurement method is changed based on the SEM image described above.

4. System Configuration (Database Management/Sharing)

An embodiment of a configuration of an apparatus according to thepresent invention will be explained with reference to FIGS. 12A, 12B. InFIG. 12A, the reference numeral 1201 denotes a mask pattern designingdevice, the reference numeral 1202 denotes a mask drawing device, thereference numeral 1203 denotes an exposure/development device, thereference numeral 1204 denotes an etching device, the reference numerals1205 and 1207 denote SEM devices, the reference numerals 1206 and 1208denote SEM control devices for respectively controlling the SEM devices,the reference numeral 1209 denotes an Electronic Design Automation (EDA)tool server, the reference numeral 1210 denotes a database server, thereference numeral 1211 denotes a storage for storing a database, thereference numeral 1212 denotes an image processing andimaging/measurement recipe creation calculation device, the referencenumeral 1213 denotes an imaging/measurement recipe server, the referencenumeral 1214 denotes a shape measurement/evaluation tool server for thecreated pattern, and these constituents are capable of communicatinginformation via a network 1220. The database server 1210 is providedwith the storage 1211 attached thereto, and some or all of (a)coordinates of EPs, (b) design data, (c) dimension measurement type/MP,(d) creation rule of recipe (including estimation rule of dimensionmeasurement type/MP), (e) recipe created, (f) image taken along theactual imaging sequence, (g) measurement results, (h) success andfailure of imaging or measurement, and (i) cause of failure of imagingor measurement can be stored and retrieved in conjunction with model,manufacturing process, data acquisition device.

Further, although in the drawing, the two SEM devices 1205, 1207 areconnected to the network, for example, in the present invention, it ispossible for an arbitrary number of SEM devices to share theimaging/measurement recipes by the database server 1211 or theimaging/measurement recipe server 1213, and it is possible to operatethe plurality of SEM device by a single imaging/measurement recipecreation. Further, by sharing the database among the plurality of SEMdevices, the success and failure of the imaging or measurement and thecauses of the failure in the past can quickly be accumulated, and byretrieving the records, some help is obtained for creating preferableimaging/measurement recipes.

FIG. 12B shows an example of integrating the SEM control devices 1206and 1208, the EDA tool server 1209, the database server 1210, the imageprocessing and imaging/measurement recipe creation calculation device1212, the imaging/measurement recipe server 1213, and the shapemeasurement/evaluation tool server 1214 shown in FIG. 12A into a singledevice 1216. As described in the present example, it is possible todivide any desired functions into an arbitrary number of devices, or tointegrate any desired functions for execution.

5. GUI

FIG. 13 shows an example of GUI for performing the setting and displayof input/output information in the present invention. The various piecesof information drawn in the inside of the window 1300 in FIG. 13 can bedisplayed on a display screen in one frame or divided into severalframes. Further, “*” in FIG. 13 represents a certain number (characterstring) or a range of a numerical value input to the system or outputtherefrom.

In the window 1320, 1321, the recipe creation rule is designated ifnecessary. It is possible to input default values. In the recipecreation rule, the windows 1320, 1321 specifically displays theparameters for setting the dimension measurement type/MP estimationrule, for example, it is possible to set the estimation rule based onthe attribute information (candidate of the dimension measurement type,candidate of possible defect, circuit attribute, easiness ofdeformation, measurement dimension on the design data, distance from thecenter of the EP, etc) obtained in each of pattern regions. In otherwords, if there is a numerical value requirement needs to be satisfiedby each of the pieces of attribute information of the finally selecteddimension measurement type/MP with respect to the plurality of dimensionmeasurement type/MP included in the EP, the numerical value is input inthe window 1320. Further, if there is the attribute information needs tobe evaluated with importance in estimating the dimension measurementtype/MP, it is possible to input the evaluation weight in the window1321.

In the windows 1324, 1325, and 1337, there is displayed information of aplurality of recipes. As the information displayed on each of thewindows 1324, 1325, and 1337, the user can input a designated value, thevalue prepared inside the system can be provided as the default value,or the recipe creation engine inside the system can estimate and output.Hereinafter, the displayed contents will be explained specificallypicking up the EP whose ID displayed in the “EP ID” column is 1 (notethat the corresponding items in the EP whose ID is 2 is described in theparenthesis).

In the window 1325, there are displayed a circuit pattern 1326 (1332) inthe EP (a SEM image, the design data, or both of them), the dimensionmeasurement cursors 1327, 1328 (1333), the imaging sequence 1329 (1334)for imaging the EP (e.g., the coordinate of the adjustment points, therange/shape, and the imaging conditions, although in the drawing, theorder is set as AP1→AP2→AF→EP (in the case with ID=2, AP→AST→AF→EP), theadjustment templates passed through are different between the EPs),information 1330 (1335) related to the EP (the coordinates of the EP,the range/shape, the imaging conditions, etc), the information 1331(1336) related to the MPs in the EP (the coordinates, the dimensionmeasurement type, the coordinates/dimension/shape of the dimensionmeasurement cursor, the dimension measurement method). It is possible todisplay the attribute information 1338 (1339) on the window 1337. If aplurality of MPs exists in the EP, the information of the MP such as theinformation 1331 (1336) related to the MP, the attribute information1338 (1339) in the MP, it is possible to display the information foreach of the MPs.

A part of or whole information is determined in response to pressing therecipe creation button 1322. Further, although in the windows 1324,1325, 1337, the information related to the plurality of EPs is displayedvertically in the order of the ID, it is possible to sort the displayorder of the EPs with a desired criteria, or limit the EP to bedisplayed. The desired criteria can be designated using a pull-down menu1323. As examples of the criteria, there can be cited (a) displaying theEPs in ascending order of the estimation accuracy of the dimensionmeasurement type/MP (the reliability of the estimation is calculated inthe dimension measurement type/MP estimation, and sorting is executedbased on the reliability), (b) eliminating the EP failed to estimate thedimension measurement type/MP from displaying (e.g., the EP causing thewarning in the step 514 shown in FIG. 5), (c) eliminating the EP, whoseposition/dimension/shape have been changed, from displaying (e.g., theEP having the state changed from the initial state provided by the userby changing the imaging range, merging with another EP, or dividing),(d) displaying only the EP including a plurality of MPs. By sorting theinformation from a plurality of viewpoints as described above, when aproblem occurs in a recipe, or when a problem may occur, it becomespossible to execute GUI display while sorting the cause of the problembased on the cause, thus problem analysis and correction can efficientlybe executed.

The imaging sequence 1329 can be visualized and then displayed on thewindow 1301. On the window 1302, the imaging sequence for imaging the EPwith the ID of “first” is visualized as AP1 (1303)→AP2 (1304)→AF(1305)→EP 1306). Further, the display method in the window 1301 can beprovided with a several options. As examples of such options provided tothe display method, there are cited a designation (check box 1317) ofthe stacked layer to be displayed, a switching option (check box 1318)for switching the display of the coordinate gauge displayed in the frame1302 between the relative coordinate from the EP and the absolutecoordinate (from a certain reference point), designation of the displaymagnification (1319), and so on.

Further, the window 1307 shows the table of the EPs. In the window, thereference numerals 1308 through 1311 denote the initial EPs designatedby, for example, the user, and by pressing the optimization button 1316,if necessary, for example as shown in FIG. 8, change of the imagingrange of the EP, merging of a plurality of EPs, or division of the EP isexecuted. The reference numerals 1312 through 1315 are optimized EPs.From the viewpoint of the relationship between the EPs before theoptimization and the EPs after the optimization, it is understood, forexample, that the EP1 (the EP with the first ID) before the optimizationand the EP2 (the EP with the second ID) before the optimization aremerged into a new EP1. Further, by checking the check box displayed onthe left of the display of the EPs 1308 through 1315, it is possible todisplay the EP, which is provided with the check, in the window 1301.

It should be noted that although in the embodiments described above, therecipe creation in the SEM device is explained, the present inventioncan be applied not only to the SEM devices, but also to opticalmicroscopes, scanning probe microscopes (hereinafter referred to asSPM), and so on. In other words, in the optical microscope or the SPM,there are some cases in which the desired EP is observed, and themeasurement is executed on the MP in the EP, and therefore, theautomatic recipe creation method, the data managing method, and thesystem configuration, the GUI, and so on described in the presentinvention can be utilized therefor. In the SPM, the SEM image describedin the embodiments is replaced with the depth information obtained bythe SPM or the image obtained by converting the depth information (byconverting the depth value into the brightness value).

Due to the reduction of design margin associated with theminiaturization and density growth of the LSI, the number of evaluationpoints at which the dimensional control of the semiconductor pattern isrequired is dramatically increasing, and the improvement in thethroughput and the improvement in the ratio of automation are stronglydesired to the SEM device and so on used as the dimensional controltool. The present invention relates to an automatic recipe creation ofthe SEM device. According to the present invention, it becomes possibleto image and measure a number of evaluation points with high ratio ofautomation, at high speed, and with high accuracy, thus patterndesigning of a semiconductor device, and the feed-back to themanufacturing process become possible.

1. A method of measuring a dimension of a circuit pattern, which isformed on a substrate, using a scanning electron microscope (SEM),comprising the steps of: (a) inputting a center coordinate of an SEMimage area including a circuit pattern having a dimension to be measuredout of the circuit pattern formed on the substrate, and designinformation of the circuit pattern including the circuit pattern havingthe dimension to be measured, and formed on the substrate; (b) setting ameasurement object area including an edge of the circuit pattern havingthe dimension to be measured, using the center coordinate of the SEMimaging area and the design information input, and setting an imagingarea and imaging condition for imaging an area including the measurementobject area with the scanning electron microscope; (c) setting animaging sequence for imaging the imaging area with the scanning electronmicroscope for measuring the dimension of the circuit pattern; (d)imaging the circuit pattern formed on the substrate with the scanningelectron microscope based on the imaging condition and the imagingsequence; and (e) processing the image obtained by imaging to measurethe dimension of the circuit pattern, wherein, step (b) includes thesteps of setting, as the measurement object area, an area including theedge of the circuit pattern in the vicinity of the position at which thedimension of the circuit pattern is measured, and setting in accordancewith a direction of the edge of the circuit pattern included in thearea, a direction of continuous scanning of an electron beam scanned inthe scanning electron microscope.
 2. The method of measuring a dimensionof a circuit pattern according to claim 1, wherein, step (b) includesthe steps of setting a type of the dimension to be measured using thecenter coordinate of the SEM imaging area and the design information,and setting the measurement object area in accordance with the type ofthe dimension to be measured.
 3. The method of measuring a dimension ofa circuit pattern according to claim 1, wherein, in step (e), the imageobtained by imaging is processed to measure any one of a line width of aline pattern, a dimension of a gap between the line patterns, an amountof recession of end of the line pattern, a diameter of a contact hole inthe circuit pattern, and an OPC shape of the circuit pattern.
 4. Themethod of measuring a dimension of a circuit pattern according to claim1, wherein, step (a) includes the steps of inputting a candidate defectfor designating a candidate of a possible pattern formation defect inthe SEM imaging area, setting a type of the dimension to be measuredusing the candidate defect, the center coordinate of the SEM imagingarea, and the design information, and setting the measurement objectarea in accordance with the type of the dimension to be measured.
 5. Themethod of measuring a dimension of a circuit pattern according to claim1, wherein step (b) includes one of the steps of changing the centercoordinate of the SEM imaging area input using the measurement objectarea and the direction of continuous scanning of the electron beam, andmerging a plurality of the imaging areas to newly set a single imagingarea using the measurement object area and the direction of continuousscanning of the electron beam.
 6. A method of measuring a dimension of acircuit pattern, which is formed on a substrate, using a scanningelectron microscope (SEM), comprising the steps of: (a) inputting acenter coordinate of an SEM image area including a circuit patternhaving a dimension to be measured out of the circuit pattern formed onthe substrate, and design information of the circuit pattern includingthe circuit pattern having the dimension to be measured, and formed onthe substrate; (b) setting a measurement object area including an edgeof the circuit pattern having the dimension to be measured, using thecenter coordinate of the SEM imaging area and the design informationinput, and setting an imaging area and imaging condition for imaging anarea including the measurement object area with the scanning electronmicroscope; (c) imaging the circuit pattern formed on the substrate withthe scanning electron microscope based on the imaging condition; and (d)processing the image obtained by imaging to measure the dimension of thecircuit pattern using information of the edge of the circuit patternhaving the dimension to be measured included in the imaging area,wherein, step (b) includes the steps of setting a type of the dimensionto be measured using the center coordinate of the SEM imaging areaincluding the circuit pattern having the dimension to be measured andthe design information, and setting the measurement object area inaccordance with the type of the dimension to be measured.
 7. The methodof measuring a dimension of a circuit pattern according to claim 6,wherein, step (b) includes the steps of setting, as an area including aposition at which the dimension of the circuit pattern is measured, anarea including the edge of the circuit pattern in the vicinity of theposition at which the dimension of the circuit pattern is measured, andsetting in accordance with a direction of the edge of the circuitpattern included in the area, a direction of continuous scanning of anelectron beam scanned in the scanning electron microscope.
 8. The methodof measuring a dimension of a circuit pattern according to claim 6,wherein step (d) includes the steps of correcting, based on the imageobtained by imaging, a position of the measurement object area, whichincludes the edge of the circuit pattern having the dimension to bemeasured and is set using the design information, and measuring a shapeof the circuit pattern using position information of the edge of thecircuit pattern having the dimension to be measured included in themeasurement object area corrected.
 9. The method of measuring adimension of a circuit pattern according to claim 6, wherein, in step(d), the image obtained by imaging is processed to measure any one of aline width of a line pattern, a dimension of a gap between the linepatterns, an amount of recession of end of the line pattern, a diameterof a contact hole in the circuit pattern, and an OPC shape of thecircuit pattern.
 10. The method of measuring a dimension of a circuitpattern according to claim 6, wherein, step (a) includes the steps ofinputting a candidate defect for designating a candidate of a possiblepattern formation defect in the SEM imaging area, setting a type of thedimension to be measured using the candidate defect, the centercoordinate of the SEM imaging area, and the design information, andsetting the measurement object area in accordance with the type of thedimension to be measured.
 11. The method of measuring a dimension of acircuit pattern according to claim 6, wherein step (b) includes one ofthe steps of changing the center coordinate of the SEM imaging areainput using the measurement object area and the direction of continuousscanning of the electron beam, and merging a plurality of the imagingareas to newly set a single imaging area using the measurement objectarea and the direction of continuous scanning of the electron beam. 12.The method of measuring a dimension of a circuit pattern according toclaim 6, wherein, in step (b), a rule for setting the type of thedimension to be measured using the center coordinate of the SEM imagingarea including the circuit pattern having the dimension to be measuredand the design information is determined by at least one of acombination teaching of the center coordinate of the SEM imaging area,the design information, and the type of the dimension to be measured,and a combination teaching of the center coordinate of the SEM imagingarea, the design information, and the measurement object area.
 13. Anapparatus adapted to measure a dimension of a circuit pattern formed ona substrate using a scanning electron microscope, comprising: inputmeans for inputting a center coordinate of an SEM image area including acircuit pattern having a dimension to be measured out of the circuitpattern formed on the substrate, and design information of the circuitpattern including the circuit pattern having the dimension to bemeasured, and formed on the substrate; imaging condition setting meansincluding a measurement object area setting section adapted to set ameasurement object area including an edge of the circuit pattern havingthe dimension to be measured, using the center coordinate of the SEMimaging area and the design information input, and an area/conditionsetting section adapted to set an imaging area and imaging condition forimaging an area including the measurement object area with the scanningelectron microscope; imaging sequence setting means for setting animaging sequence for imaging the imaging area, which is set by theimaging condition setting means for measuring the dimension of thecircuit pattern, with the scanning electron microscope; scanningelectron microscope means for imaging the circuit pattern formed on thesubstrate based on the imaging condition set by the imaging conditionsetting means and the imaging sequence set by the imaging sequencesetting means; and image processing means for processing the imageobtained by imaging with the scanning electron microscope means tomeasure the dimension of the circuit pattern, wherein, the measurementobject area setting section of the imaging condition setting means sets,as an area including a position at which the dimension of the circuitpattern is measured, an area including the edge of the circuit patternin the vicinity of the position at which the dimension of the circuitpattern is measured, and the imaging condition means further includes ascanning direction setting section adapted to set a direction ofcontinuous scanning of an electron beam scanned in the scanning electronmicroscope in accordance with a direction of the edge of the circuitpattern included in the area set by the measurement object area settingsection.
 14. The apparatus adapted to measure a dimension of a circuitpattern according to claim 13, wherein the imaging condition settingmeans further includes a dimension measurement type setting sectionadapted to set a type of the dimension to be measured using positioninformation of the circuit pattern having the dimension to be measuredand the design information, and sets the area including the edge of thecircuit pattern as the measurement object area in accordance with thetype of the dimension to be measured set by the dimension measurementtype setting section in the measurement object area setting section. 15.The apparatus adapted to measure a dimension of a circuit patternaccording to claim 13, wherein the image processing means includes ameasurement object area correction section adapted to correct a positionof the measurement object area, which is set by the measurement objectarea setting section of the imaging condition setting means using thedesign information, based on the image obtained by imaging with thescanning electron microscope means, and a dimension measurement sectionadapted to measure the dimension of the circuit pattern using theposition information of the edge of the circuit pattern having thedimension to be measured included in the measurement object areacorrected by the measurement object area correction section.
 16. Theapparatus adapted to measure a dimension of a circuit pattern accordingto claim 15, wherein, the dimension measurement section of the imageprocessing means processes the image obtained by imaging with thescanning electron microscope means to measure any one of a line width ofa line pattern, a dimension of a gap between the line patterns, anamount of recession of end of the line pattern, a diameter of a contacthole in the circuit pattern, and an OPC shape of the circuit pattern.17. An apparatus adapted to measure a dimension of a circuit patternformed on a substrate using a scanning electron microscope, comprising:input means for inputting a center coordinate of an SEM image areaincluding a circuit pattern having a dimension to be measured out of thecircuit pattern formed on the substrate, and design information of thecircuit pattern including the circuit pattern having the dimension to bemeasured, and formed on the substrate; imaging condition setting meansincluding a measurement object area setting section adapted to set ameasurement object area including an edge of the circuit pattern havingthe dimension to be measured, using the center coordinate of the SEMimaging area and the design information input, and an area/conditionsetting section adapted to set an imaging area and imaging condition forimaging an area including the measurement object area with the scanningelectron microscope; scanning electron microscope means for imaging thecircuit pattern formed on the substrate, based on the imaging conditionset by the imaging condition setting means; and image processing meansfor processing the image obtained by imaging with the scanning electronmicroscope means to measure the dimension of the circuit pattern usinginformation of the edge of the circuit pattern having the dimension tobe measured, wherein the imaging condition setting means furtherincludes a dimension measurement type setting section adapted to set atype of the dimension to be measured using position information of thecircuit pattern having the dimension to be measured and the designinformation input by the input means, and sets the area including theedge of the circuit pattern as the measurement object area in accordancewith the type of the dimension to be measured set by the dimensionmeasurement type setting section in the measurement object area settingsection.
 18. The apparatus adapted to measure a dimension of a circuitpattern according to claim 17, wherein the area/condition settingsection of the imaging condition setting means sets a direction ofcontinuous scanning of an electron beam scanned in the scanning electronmicroscope in accordance with a direction of the edge of the circuitpattern included in the measurement object area set by the measurementobject area setting section.
 19. The apparatus adapted to measure adimension of a circuit pattern according to claim 17, wherein the imageprocessing means includes a measurement object area correction sectionadapted to correct a position of the measurement object area, which isset by the measurement object area setting section of the imagingcondition setting means using the design information, based on the imageobtained by imaging with the scanning electron microscope means, and adimension measurement section adapted to measure the dimension of thecircuit pattern using the position information of the edge of thecircuit pattern having the dimension to be measured included in themeasurement object area corrected by the measurement object areacorrection section.
 20. The apparatus adapted to measure a dimension ofa circuit pattern according to claim 19, wherein, the dimensionmeasurement section of the image processing means processes the imageobtained by imaging with the scanning electron microscope means tomeasure any one of a line width of a line pattern, a dimension of a gapbetween the line patterns, an amount of recession of end of the linepattern, a diameter of a contact hole in the circuit pattern, and an OPCshape of the circuit pattern.